# L3 Illumination K40 Thrower (1 x XM-L U2 | 3 x 18650) Review



## turboBB (Oct 13, 2012)

*L*3 Illumination is a new startup in the flashlight industry with the K40 holding the honor of being their very first product:





If the K40 bears an uncanny resemblance to ThruNite's TN31, the reason as I understand it, is akin to why Spark's products resemble Zebralight's. Let's dig deeper into the light to see whether the resemblance is merely skin deep shall we?


*MFG SPECS
*MSRP (USD): $119.99
LED: Cree XM-L U2 LED with a lifespan of 100000 hrs. 

 Max 1147 lumen output using 3 * 18650 batteries. *(Batteries not included)*
 *Level 1*: 0.5 lm. 2000 hours; *Level 2*: 21 lm. 140 hours; *Level 3*: 146 lm. 22 hours;* Level 4*: 366 lm. 9 hours; *Level 5*: 620 lm. 5 hours;* Level 6*: 1147 lm. 2 hours; *Standby:* 65 uA; *Strobe*: 1147 lm. 4 hours.
 Working voltage: 4V to 13V. 
Max runtime: 2000 hours. 
Max beam distance: 700 meters. 
Peak beam intensity: 75000cd. 
Impact resistant: 1.2 meters. 
Waterproof to IPX-8 standard, 2M. 
Size: 186(Length)x76.2(bezel diameter)x49(body diameter) unit mm. 
Weight: 452.80g without battery. 
Aircraft grade aluminum body structure. 
Premium type III hard anodized anti-abrasive finish. 
Ultra-clear tempered glass lens with anti-reflective coating. 
Momentary forward click tactical switch. 
Variable frequency strobe mode for tactical and emergency use. 
Smooth reflector for max light output. 
Highly focused beam for maximum distance. 
Intelligent highly efficient circuit board design for max performance and long run time. 
Intelligent temperature controlled light output for user safety. 


*PACKAGING / CONTENTS
*The K40 arrived in a pretty nice aluminum box:


 

 

 

Accessories included are:
- 2 x o-ring's
- lanyard
- holster
- user guide (wasn't included in my sample)






*CONDENSED VIDEO SUMMARY 
*Here is a quick high-level video summary of the K40 while while I work on fleshing out this review:


*DESIGN / FEATURES
*The K40, doesn't feature a SS bezel and makes do with crenellations at the tip of its removable Al bezel:


 

 

 
This also allows one to note if the light is on or not when stood bezel down.

The bezel was not glued down but it did take some effort to remove as while the threads were greased, there were none on the o-ring:



Once removed, the lens, reflector and LED emitter are all easily accessible.

There is another o-ring that sits recessed within a groove around the inner diameter at the tip of the bezel:


 


The lens has got some mass to it and measures 3.6mm thick.

It also features very pronounced double-sided AR coating. It is in fact so effective that at close distance, one is able to notice the blue wavelengths that are being rejected:


 

 
The blue hue is only noticeable in the spill and not the hotspot at farther distances.

The super smooth reflector measures 69.2mm in diameter by 51mm deep:


 

 

The XM-L U2 emitter sits perfectly centered thanks to a plastic centering mold:



The rim immediately surrounding the LED also helps center the reflector.

These heat fins feature prominently around the head, however, given the heatsinking path, the highest temp is actually directly around and just aft of the control ring:


 

 


 


The edges of these fins also aid w/anti-roll.

Speaking of the control ring, it controls 6 output levels along with Standby and Strobe modes. While there is an icon indicating the direction of the output levels, it's a tad short; the pic on the right has the indicator arrow pointing at level 3:


 

 
The grooves around the ring help provide additional grip during use (see Size/Handling section for details).

The tube of the light features four flat sides whereby two have laser engravings:


 

 

 
One side bears the company's name while the other has the model and serial no. The texturing is rather smooth and doesn't really contribute much to the grip.

Being a cannister-style light, the battery tube doesn't feature a traditional tailcap but rather a "integrated" one, it is however still removable (more on that later):


 

 

 
There are machined grooves similar to the ones on the control ring as well as two attachment points for the included lanyard.

These holes are large enough to accomodate the hook so as not to need the included mini ring:


 

 
However, there isn't a cut-out groove on either end to accomodate perfectly level tailstanding w/out it (which should be used for safety reasons as it functions as a "break-away" point).

Without the lanyard, the base is perfectly flat with decent material thus allowing reasonably stable tailstanding use:


 

 
The rubber tail cap switch cover sits well recessed so as to reduce accidental activation but this may potentially cause use issues (see Size/Handling section for further details).

The batteries are housed within a carrier which is accessed by removing the head:


 

 
There is a spring to help maintain connection w/the positive contact point on the carrier. 

With the cover removed, one can see the circuitry on the PCB:


 

 
It is reasonably well isolated from the heatsink that the emitter sits on as the only direct contact points are the three "poles" that the screws go into.

Here is a close up shot:


 

 
There are a total of eight "481H1" chip (close up in right pic) that corresponds with the 6 output levels and standby / strobe modes. They MUST be aligned properly with the control ring so care must be taken to reinstall the PCB correctly.

The battery carrier features redundant postive/negative contact points thus allowing it to be inserted into the tube either way w/out concer for polarity (the batteries do need to be installed in correct polarity though):


 

 
Both ends are identical w/the positive contact point isolated by a plastic grommet in the center and the outer rim carrying the negative path. How this is achieved is by clever routing on the two PCB's on each end (side k40-A and k40-B) and through the "legs" of the carrier.

Starting w/the ending negative spring on the "A" PCB of the carrier (top-left pic), it is directly connected to the outer light green parts of the PCB (dark green color represents "open" in the circuit path) and the three outer legs. These legs carry the negative path to the other end thus creating the redundancy. With the first battery is inserted at the spring, the positive point is routed to the negative spring of the second battery in series (top-right pic):


 




 

 
The second battery is inserted there and its positive point is routed to the third battery's negative spring in series (bottom-left pic). Finally, the third battery is inserted and its postive point is directly connected w/the central leg that carries the path to the other end as well.

The raised positive contact points allow the use of flat-top cells but care must be taken not to catch the heat-shrink wrap during removal (as shown in left-pic):


 

 
There is sufficient room to accommodate my shortest cells (AW IMR 1600 @ 65.2mm) and longest (XTAR 18700 @ 69.2mm). The XTAR's are incidentally also the largest in diam (18.3mm w/the label) and w/the labels and protection wire not facing the ID of the tube, I had no problems with insertion/removal of the carrier into/from the tube. YMMV depending on the diameter of your batteries. Also see Fit & Finish section re: loose heat-shrink wrapping.

Peering down the tube, one can see two springs, the center for the positive path and the outer one for the negative:


 

 

 
As previously mentioned, the tailcap cover is removable allowing access to the forward-clicky switch and PCB it's soldered to.

The supplied holster is of decent quality and covers the entire light (with exception of the exposed sides of the head):




It features both a fixed belt loop and a quick-release button that's re-inforced w/velcro for extra security.However, given the size of this light, unless one is a 7ft tall giant, IMO it'd look pretty awkward hanging off of one's belt.


*SIZE / HANDLING
*


L to R: RediLast 3100 within K40's battery carrier | Sunwayman T60CS | ThruNite TN30 | L3 Illumination K40 | Crelant 7G9 | ThruNite TN31

Here is an on-request pic w/NITECORE'S TM11 in lieu of the battery carrier:




The K40 runs mid-pack amongst the cannister style/sized lights. I had no problems with holding the light in either an overhand or underhand grip, however, the tube is a little chunky @ 48.9mm in diam (1.93") and might cause issues for those afflicted with arthritis or other ailments:


 

 


 

 
Given the girth, I found the slightly recessed switch a bit difficult to access w/my medium-sized hands thus forcing me to hold the light further back than I would've liked. The edges of the machined elements around the base also pokes into the base of my thumb. Hopefully, these will be non-issues for those w/larger hands or longer digits.

Fortunately, the control ring is easy to operate one-handed:


 

 

 
As previously mentioned the grooves in the control ring aid with grip with one's fingers placed in them.


*FIT & FINISH
*The K40 has been absolutely solid all-around. Starting w/the HA-III anodizing, it was perfectly matched on all parts:



Note: Flash was intentionally used in this shot to highlight any mismatching but none was found.

There were none missing in the grooves of the texture, around sharp edges or within the heat fin areas (these are common issues found on poor anodizing process):


 

 

 

All engravings are also nice and sharp with no blotchiness:


 

 

While the threads are not square-cut, they came well greased and I didn't have any issues w/gritiness:




In terms of nitpicks, while the control ring operates with nice solid clicks on the detents*, it wasn't greased on my sample and creates a slightly gritty feel. Also, the o-ring's weren't greased on my sample so one should check that since it may bind and potentially compromise water-resistance. Last but not least, the heat-shrink tubing around the legs were not fully shrunk thus causing some lumpiness which can steal precious room away for the batteries to fit tightly towards the center:


 

 

 

*I was informed by L3 that based on customer feedback, the springs in currently shipping models (which includes my review sample) has been upgraded to create a more solid feel.

One change I would like to see on future versions is a shortening of the tail springs so as to allow the battery carrier to sit lower when inserted thus it doesn't potentially get caught on the rim of the tube when threading the head on:



With the exception of SPARK's SP6 (which uses a different size/style carrier), this has been a common theme on all lights featuring this style of carrier that I've tested thus far.

Beyond this, I find the K40 to be truly superb in overall build quality.


*UI
*The tailcap switch acts as the master on/off. When it is off, the control ring is non-functional. With the tailcap switch on, the UI is very straightforward as follows (with light pointed away from you and going clockwise from L to R):
- Six increasing levels of output (from L1 @ .5lms through L6 @ 1147lms)
- Standby
- Strobe

The levels are generally well spaced, although I find that visually, there doesn't seem to be a very distinct difference between levels 6 to 5 and 5 to 4. It would have been better if these were spaced further apart. The super low of .5lms makes the light very usable with dark adapted eyes but given it is a thrower after all, I personally don't find the pinpoint hotspot to be particularly useful. The Standby mode is handy since it allows the light to be "shut-off" with one-handed use rather than having to reach around to the tail-cap to shut it off. Current draw is absolutely trivial (59.7µA) so is of no concern (see Runtime section for further details).


*BEAMSHOTS
Indoors (5m)*
L6






 

 

 

L5


 

 

 

L4


 

 

 

L3


 

 

 

L2


 

 

 

L1


 

 

 
For details of the above indoor shots and comparo vs. many other lights, please check Epic Indoor Shots Trilogy


*RUNTIME
*The relevant battery stats are provided above each runtime graph along with: 
- Voltage of the battery at the start and end of the test
- Current draw
- Actual runtime using ANSI FL1 (first in HR and then in M so for the RL3100 on High, read this as 1.7hrs *or* 100min)
- NEW (as of May 2012): Lumens measured on my PVC LMD @ 30 seconds
- Also for High, captured the temperature: ambient, the head/fins at start and the max it reached (fan was used for all bats)



The run with either set of cells is nearly identical to that of the TN31's that I graphed. The major exception is that at the end of the run, rather than giving a low voltage warning and then shutting off, the K40 will actually kick down to the lowest mode. I felt this was a nice touch rather than leaving one suddenly and completely in the dark. However, it's worth noting that the cells are already pretty drained at this point so prolonged use at this level is not recommended.

Of note is that the current measurements I took are without the tailcap and is inline w/the batteries so in a way, mimicking tailcap readings. There's also the matter of the resistance introduced in the less than stellar wiring with this setup so I am not able to match the claimed 3.5A draw on max. These readings are slightly lower than what I measured on the TN31 (which in turn was slightly lower than what HKJ measured for his sample of a TN31). I'm working w/L3 Illumination to determine how their reading was done and if possible to replicate the setup.

For now, here are the measurements I took for each set of batteries (in mA) and the calculated runtime (in hrs) for each level:







 

 

 

 

 


L to R: Current draw readings for L6 to L1 on 3xRL3100's. Nominal voltage = 10.8v (3.6x3).

Standby is absolutely trivial @ 59.7µA and put into perspective (while leaving battery self-discharge and leap years out of the pic) would calculate to ~52K hrs or 2163.6hrs/5.93yrs:





*INITIAL CONCLUSION
*As should be obvious by now, the K40 is not a straight-up clone of the TN31. If anything, it's like a TN31-lite or TN30.5. Regardless of what one may call it, it offers tremendous value for the buck in terms of both performance and build quality. While there is yet another variation of this light known as the Supbeam K40, L3's iteration is driven to 3.5A (vs. 3.0A for Supbeam's). This is a solid first release from L3 Illumination and I'm definitely looking forward to what else they might have in store for us. Until then, here are my thoughts for now:

*turboBB-licious
*- superb overall build quality
- cotrol ring allows quick and direct access to 6 output levels w/Strobe off to the side and not required to be accessed unless desired
- edges of heat-sink fins function as anti-roll, especially useful on such a large light
- great performance, throw and runtime given the form factor

*turboBB-cautious
*- claimed 1147lms is before step-down but even so, average output of entire run on L6 after step-down is still 1062lms (as measured on my PVC LMD)
- control ring and o-ring's not greased on my sample (merely an inconvenience in the case of the former but a potential compromise of water-resistanace is possible with the latter)
- no cut-outs for lanyard when used thus preventing stable tailstanding (well... you know I'm really hunting if I have to mention things like this under the cautious section... ;o))
- unestablished track record for this new company, however, it was founded by a well-known and reputable dealer 

*turboBB-wishes
*- slightly shorter tailcap springs to allow face of battery carrier to sit flush w/battery tube
- L3 Illumination, what other products are you working on? Inquiring flashaholic-minds want to know! 


*K40 GALLERY*



=======
Disclosure: K40 provided by sbflashlights for review.


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## turboBB (Oct 13, 2012)

Video is still uploading so please check back in a few min if you don't see it. I'll be fleshing this out over the weekend.


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## kj2 (Oct 13, 2012)

Thanks


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## sbbsga (Oct 13, 2012)

Does the control ring require more force to turn than TN31's?

Thank you.


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## Bwolcott (Oct 13, 2012)

i got mine and I am loving it for the money!


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## ILIKEFLASHLIGHTS (Oct 13, 2012)

Thanks Tim.

I just got done ordering this K40 for my birthday later this month.


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## Yourfun2 (Oct 14, 2012)

Every time I come back to thinking this should be my next light, I realize it doesn't come in neutral. Bummer!


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## Overclocker (Oct 14, 2012)

Yourfun2 said:


> Every time I come back to thinking this should be my next light, I realize it doesn't come in neutral. Bummer!



plenty of modders who would be happy to dedome and reflow a neutral of your choice


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## turboBB (Oct 14, 2012)

sbbsga said:


> Does the control ring require more force to turn than TN31's?


Not really, the feel is nearly identical except that on the K40, it's not greased on my sample.




Bwolcott said:


> i got mine and I am loving it for the money!





ILIKEFLASHLIGHTS said:


> I just got done ordering this K40 for my birthday later this month.


Congrats guys! It offers great performance and bang for the buck. ILF, here's an early "HAPPY B'DAY TO YOU!"




Yourfun2 said:


> Every time I come back to thinking this should be my next light, I realize it doesn't come in neutral. Bummer!


I think if enough interest is shown, it'll be considered, check reply #16 here.


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## jake25 (Oct 14, 2012)

Neutral white will be considered for the next run.


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## RBH (Oct 14, 2012)

Turbo

Sorry if this has been asked already, have you had the K40 and TN31 out for a side by side beam comparison ?

Thanks Bruce


turboBB said:


> Not really, the feel is nearly identical except that on the K40, it's not greased on my sample.
> 
> 
> 
> ...


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## turboBB (Oct 14, 2012)

Runtime on Max and current draw readings added.

@RBH - not yet but based on around the house use, the TN31 has a slightly tighter hot spot and a little less spill (given the deeper reflector) vs. the K40 (becomes more noticeable the further past >5ft you aim the beams). Performance is comparable otherwise with a very slight edge to the TN31. I should have indoor shots up tomorrow.

Cheers,
Tim


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## Overclocker (Oct 14, 2012)

K40 initial LED current. settles at ~3.5A


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## turboBB (Oct 15, 2012)

Where (LED?)/how are you measuring this? My setup likely has a lot of resistance. 

Thx!,
Tim


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## RBH (Oct 15, 2012)

Has there been any mention of a warranty on these ? If the tail switch should fail, is that a generic part ?

Thanks Bruce


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## Overclocker (Oct 15, 2012)

turboBB said:


> Where (LED?)/how are you measuring this? My setup likely has a lot of resistance.
> 
> Thx!,
> Tim



yes tim, a dmm inline with the LED so you'll need to unsolder one wire. cheapo (and very dusty!) dmm but modded for low resistance, plenty accurate


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## turboBB (Oct 15, 2012)

Thx OC, I'll give that a shot later.

@RBH - As printed on the user manual "Flashlight products that are found to be defective under normal use within 24 months of the period of purchase date will be repaired or replaced without charge." Not sure where you're located but the dealer is US based. 

As for the switch, it is actually a standard mechanical forward-clicky but it is soldered to a PCB w/add'l components which is not so standard:




EDIT: Size comparo pic added to OP.


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## RBH (Oct 16, 2012)

Thanks Tim 

Does that make the switch basically non replaceable ?


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## turboBB (Oct 16, 2012)

Leaving warranty out of the pic, if it's just purely the mechanical clicky and one is reasonably skilled w/a solder, it can be replaced. If it's the entire PCB w/the switch, that's easilly swapped out if you had a replacement. The tailcap cover simply unscrews and you just grab the switch/PCB and it comes right out. No special tools required beyond your hands.


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## RBH (Oct 16, 2012)

Thanks Tim


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## dajabec (Oct 17, 2012)

Is there a lux reading hidden somewhere in the review?


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## Bwolcott (Oct 17, 2012)

dajabec said:


> Is there a lux reading hidden somewhere in the review?




Im think he mentioned it in the video but I watched it a few days ago so I may be wrong


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## turboBB (Oct 17, 2012)

77k lux @ 1m (vs. 87k lux for TN31). My lux readings tend to be lower vs. other reviewers so I feel the 90k lux @ 1m claim by L3 is very reasonable.


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## jake25 (Oct 17, 2012)

On my lux meter I read 110k lux @1m for the TN31 (Selfbuilt read 112k). On the K40 I got 87k lux @1m


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## jorgemac (Oct 17, 2012)

jake25 said:


> On my lux meter I read 110k lux @1m for the TN31 (Selfbuilt read 112k). On the K40 I got 87k lux @1m



Wow, 110k vs 87k remarkable difference with the TN31.


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## Bwolcott (Oct 17, 2012)

jorgemac said:


> Wow, 110k vs 87k remarkable difference with the TN31.



I cant tell a big difference in person


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## turboBB (Oct 17, 2012)

Indoor shots (5m) now added. Design & Features section in progress.


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## ILIKEFLASHLIGHTS (Oct 18, 2012)

The sample I have actually out throws my Fenix TK70 I do believe. I'm truly impressed.


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## biglights (Oct 18, 2012)

ILIKEFLASHLIGHTS said:


> The sample I have actually out throws my Fenix TK70 I do believe. I'm truly impressed.



Pics? That would put it at over 100k. WOW.


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## ILIKEFLASHLIGHTS (Oct 19, 2012)

Well here's a beamshot of the K40 at about 400yds with not as much zoom as the others I will show comparing the K40 against the TK70. These are all taken on manual eposure with a 1.4 sec shutter, f/4 and ISO 400. 







Now here's the same shot zoomed in more to show you more in detail. 






Now here's the Fenix TK70.


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## ILIKEFLASHLIGHTS (Oct 19, 2012)

I hope Tim doesn't mind me posting the pictures here. Tim does an excellent job on all of his reviews.


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## turboBB (Oct 19, 2012)

Not at all man! Your outdoor pics are great references for those looking for real world comparos so by all means, please post away. :thumbsup:


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## biglights (Oct 19, 2012)

Nice review Tim and thanks for the pictures.


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## lintonindy (Oct 19, 2012)

Thank you for the review. Mine was ordered yesterday afternoon after reading this and other reviews. I'm really excited!


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## lintonindy (Oct 19, 2012)

*SIZE / HANDLING



L to R: RediLast 3100 within K40's battery carrier | Sunwayman T60CS | ThruNite TN30 | L3 Illumination K40 | Crelant 7G9 | ThruNite TN31

If I could take this picture and replace the battery carrier with a tiny monster or another chunky light it would be my new screen saver!

*


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## turboBB (Oct 19, 2012)

Here you go (click on pic for full size):



Enjoy!


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## lintonindy (Oct 19, 2012)

turboBB said:


> Here you go (click on pic for full size):
> 
> 
> 
> Enjoy!



You da man! Thank you very much!


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## Bwolcott (Oct 19, 2012)

dang I didnt realize how small the tm11 actually is


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## RBH (Oct 19, 2012)

I just compared mine to a Stanley HID on some different targets from around 100 to a little over 400 yards. The K40 is surprisingly close in throw and brightness to the Stanley after it ramps down. I did notice that the K40 has a rather pronounced doughnut hole like my G5 Maelstrom, not saying this is a problem, it's just something I found noticeable. From what I see so far, I would say this light is crazy good for the price, and with the two year warranty and prompt service from sbflashlights, "the light was packaged for shipping by someone who actually cares," I wouldn't think twice about it, do yourself a favor and buy one. I also noted that the selector ring on mine is smooth and positive in operation.

Should a person leave the tail switch on and just use the selector ring to turn the light off to keep from wearing out the tail switch ?

Thanks Bruce


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## RBH (Oct 19, 2012)

Here are a couple of poor quality beam shots of a hay bale at maybe 75 or 80 yards away. I'll put my Epl1 on the tripod and try for some better ones when I get a chance. 


Stanley HID 







K40


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## Overclocker (Oct 22, 2012)




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## Bwolcott (Oct 22, 2012)

excellent pictures!


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## turboBB (Oct 22, 2012)

Thx for posting the great beamshots guys!

All, as an upate, this review is just about wrapped up (still need whitewall & outdoor shots). This is a fantastic gem from L3, can't wait to see what else they might be working on. 

Cheers,
Tim


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## ZRXBILL (Oct 22, 2012)

turboBB said:


> This is a fantastic gem from L3, can't wait to see what else they might be working on.
> 
> Cheers,
> Tim




I hope they're working on a 3 LED version.


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## jorgemac (Oct 22, 2012)

turboBB said:


> Thx for posting the great beamshots guys!
> 
> All, as an upate, this review is just about wrapped up (still need whitewall & outdoor shots). This is a fantastic gem from L3, can't wait to see what else they might be working on.
> 
> ...



What are the main difference between this light and TN31?, thinking especially in quality construction and performace.


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## turboBB (Oct 22, 2012)

*EDIT 11/18*: I retook the indoors 5m pics and have updated the pics below so that now they are a true 1:1 comparo.

They are just about identical in quality / construction. Beyond the subtle styling differences, the K40 is:

- more compact owning to shorter reflector (51mm vs. 64mm)

- slightly less throw (77k lux @ 1m vs. 87k)

- just slightly less output (K40 left @ 1200lms vs. TN31 right @ 1270lms as measured on my PVC LMD - not really distinguishable by eye)




 
L: K40 | R: TN31 

- although it doesn't look like it due to the intensity of top shots (@ 1/4" & bottom @ 1/80"), the hotspot is slightly larger (which becomes more noticeable > 5 ft.); overall spill is slightly larger:


 




 

 
L: K40 | R: TN31 

- much cheaper price wise

- lacking a SS bezel

- features different AR coating (K40 is geared more towards blue wavelengths) 

Here's a quick side-by-side I just took @ ~1ft (ISO80, AWB, _f_/8 & 1/320 for left | 1/4000 for right):


 


K40 left | TN31 right in both pics.

Hope that helps.

Cheers,
Tim


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## hahoo (Oct 22, 2012)

turboBB said:


> They are just about identical in quality / construction. Beyond the subtle styling differences, the K40 is:
> 
> - more compact owning to shorter reflector (51mm vs. 64mm)
> 
> ...





looks like that tn31 is trying to burn a hole in that door !!:devil:
i sure have enjoyed mine so far..
it is good to see one thats half priced and even in the ballpark with the 31...
good reviews bb...we appreciate your time and effort on all your hard work sir...


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## ILIKEFLASHLIGHTS (Oct 22, 2012)

Here's one I took of my K40 at 60yds on manual exposure with 1.2 sec shutter speed because I thought that 1.4 sec may overexpose the bright beam that this light puts out up close.


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## RBH (Oct 23, 2012)

From what I see here, I bet it would be almost impossible to see a difference if you were outside and had the TN31 in one hand, the K40 in the other. If you like the smaller size of the K40, and I definitely do, it makes it that much more appealing.

Bruce



turboBB said:


> - slightly less throw (77k lux @ 1m vs. 87k)
> 
> - just slightly less output (K40 left @ 1200lms vs. TN31 right @ 1270lms as measured on my PVC LMD - not really distinguishable by eye)
> 
> ...


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## Bwolcott (Oct 23, 2012)

RBH said:


> From what I see here, I bet it would be almost impossible to see a difference if you were outside and had the TN31 in one hand, the K40 in the other. If you like the smaller size of the K40, and I definitely do, it makes it that much more appealing.
> 
> Bruce




your right ive tried both side by side and its really hard to tell


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## RBH (Oct 23, 2012)

That decisive statement based on your firsthand experience should help a lot of people choose between the two. It looks like the price of the TN31 is coming down, but I would still choose the K40 based on size. I find it to also be an outstanding general purpose light with the very decent spill and several easy to access modes. Makes my Mag light seem like a real POS. 



Bwolcott said:


> your right ive tried both side by side and its really hard to tell


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## turboBB (Nov 18, 2012)

I retook the indoor shots to allow 1:1 comparo. Rather than reposting everything, I've updated my orginal comparo shots in reply #46 above.

Cheers,
Tim


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## RBH (Nov 27, 2012)

When my K40 steps down from hi, the X-Star 3100's are all at 3.3 volts. Is that a reasonable level, or to low. If it causes minimal damage, I would prefer not to go through the topping off routine any more than I have too.

Thanks Bruce


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## TEEJ (Nov 27, 2012)

RBH said:


> When my K40 steps down from hi, the X-Star 3100's are all at 3.3 volts. Is that a reasonable level, or to low. If it causes minimal damage, I would prefer not to go through the topping off routine any more than I have too.
> 
> Thanks Bruce



Those cells should actually be able to go down to closer to ~ 2.8 v if the light doesn't cut out before that.


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## RBH (Nov 27, 2012)

Thanks for the reply. The light stays nice and bright, then just steps down in level in a instant. It doesn't get any better than that.


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## TEEJ (Nov 27, 2012)

Its typically temperature related in those cases...rather than current related, unless the cells lost the ability to supply enough amperage despite the adequate voltage, etc.


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## RBH (Nov 27, 2012)

Thanks


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## RBH (Dec 15, 2012)

Here are a couple of shots I took before my camera battery died. The cement corner post has a white bucket on top of it at 130 yards.

Bruce







L3 Illuminations K40






Stanley HID


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## AGT Tactical (Nov 22, 2013)

Any one know which flashlight is better quality...the K40 made by L3 Illumination, or the K40 made by SupBeam? Or are they made by the same outfit under different names? 

And thank for the great write up! You are the best!


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## Overclocker (Nov 22, 2013)

AGT Tactical said:


> Any one know which flashlight is better quality...the K40 made by L3 Illumination, or the K40 made by SupBeam? Or are they made by the same outfit under different names?
> 
> And thank for the great write up! You are the best!




K40 is made by supbeam. L3 is just a rebrand. Supbeam will etch any logo you want if you buy a certain quantity


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