# Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights)



## turboBB (Aug 22, 2011)

*Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights)*





It's been a while since I've had a new Fenix. Back in early 2008 when I first got into this hobby, a L0D was actually the second light I added to my then budding collection. That was followed by a LD10 in early 2009 but I gave that away shortly after acquistion to one of my in-law's. As the years went on since the LD10, for whatever reason I just didn't acquire another Fenix light even though I've had great experiences with the two. The L0D was actually my EDC for a while but had fallen out of favor as I prefer 1 x 123 format. My "New Fenix-less" status changed back in June as I was one of the lucky winners of a give-away for a Fenix TK21 U2 on CPFMP.

Let's see what Fenix has to offer in one of their latest releases. 


*MANUFACTURER SPECS*
• Cree XM-L (U2) LED with a lifespan of 50,000 hours
• Uses two 3V CR123A batteries (Lithium) or one 18650 rechargeable battery (Li-ion) 
• 150mm (Length) x 25.4mm (Diameter) x 40mm (Head)
• 152.6-gram weight (excluding batteries)
• Digitally regulated output - maintains constant brightness
• Reverse polarity protection, to protect from improper battery installation
• Push button switch with momentary-on function
• Made of durable aircraft-grade aluminum
• Premium Type III hard-anodized anti-abrasive finish
• Toughened ultra-clear glass lens with anti-reflective coating


*PACKAGING*



The packaging is standard fare for lights in its class with an outer cardboard box with a display window showcasing the light and then there is a plastic inner shell that holds the light, accessories and manual. There is no indication on the box that this is the Special Edition U2 version, however, the manual does state it's an U2:




Supplied with the light were:
- User Manual
- Warranty sheet
- Holster
- 2 x Powerizer CR123
- Accessories bag containing:
* 1 x spare rubber tailcap cover
* 1 x spare o-ring
* 1 x wrist strap (it's a stretch to call this a lanyard)


*DESIGN/FEATURES*



The TK21 features Cree's XM-L LED and the U2 designation means that it's using the highest luminous bin vs. the more common (for now) T6. The claimed output is also up slightly from 449 lumens for the T6 to 468 lumens for the U2.



EDIT: 8/27 Apparently, this was the only version ever released as Fenix was able to secure sufficient amounts of U2 bin and thus never released a T6 version.

The mini-turbo head is a single integrated unit that does not feature a removable bezel. I've noticed that it seems to be increasingly common with recently released lights that the head is glued and not-removable as well. While the manual states that the glass features anti-reflective coating, I wasn't able to see this on the outside (usually indicated by the tell-tale blue reflection):





Perhaps it was only applied on the inside.

The tip of the head is also completely flat so it'll sit flush against a flat surface when stood on it's head thus you won't be able to tell if the light is on or not (I tipped the light slightly in the last shot to show that it was indeed on):






The engravings are very fine and sharp with no noticeable defects. What i found interesting though is that the HOT symbol was engraved over different angles without any flaws whatsoever:



I'm not familiar with the process so perhaps someone more knowledgeable can pipe in on how it's done.

While we're on the topic of the HOT symbol; the light for the most part respects design symmetries (e.g. the Logo and Model are centered with the button, the cut angles and different facets are symmetrical on both sides). Where this deviates is, you guessed it, the HOT symbol (and the serial number). They are not centered with the button or logo/model. Neither is the groove on the head: 




Ultimately not a big deal and symmetrophobes would feel right at home with this aspect.

Around the "throat" of the light, we find a silver button that controls level changes (more on this later). The button sits on a flat surface that is also featured on the opposite side (again respect to symmetry comes in to play here).





This was actually a very thoughtful design as the tip of the index finger rests on this flat surface (right pic) providing stability when depressing the button.

There is a tactical-ring that can aid with anti-roll which can be removed revealing non-squared threads:





However this didn't detract from the smoothness when screwing it on.


The rubber boot on the tailcap extends past the end of the prongs on the tail and as such, renders it non-tailstandable:




The light features springs in both the head and tail ends which should help absorb shock and even when I shook it very hard, I was not able to induce any battery rattle:






Removing the tailcap exposes nice squared threads:



As can be seen above, a AW2600 just peaks out of the tube so longer batteries might pose a problem so you may wish to check this before committing to a purchase if you have really long batteries

EDIT: 8/27 new material
While the holster accomodates the light snugly, I feel it was either more of an afterthought or a generic one that was repurposed for this light as the flap seems just a little short and thus exposes the Velcro to the head of the light which in the long run, may potentially scratch up the finish: 




 

As for the strap (bottom one in the pic), after playing it around with it a bit, I'm sure it's more than up to the task of securing the light in case it slips however, it just doesn't inspire the same confidence that a true lanyard gives:




*SIZE*
Owing to the mini-turbohead (1.53" in diameter), the light is towards the larger end of the 1x18650, 2x123 sized lights:






From L to R: Fenix TK21 | SF U2 | Olight M20 | SF E2DL | SF Z2 | SF G2Z | SF L4 | SWM T20C

I can definitely feel a bias in weight towards the head but nothing overbearing so as to make it very unbalanced.


*FIT/FINISH*
Fit and finish is as I recall my earlier Fenix's to be which is pretty good. The HA finish is flawless and matched perfectly between all parts:



(flash was intentionally used to try to expose mismatches in the anodizing but as you can see, there is none to be found)

The textured finish on the tube is a bit smooth and doesn't really offer much in the way of additional grip, however the texture on the tailcap is a bit better and improves grip when changing batteries:






However, looking down the battery tube, I noticed some residual burr from what looks to be the mating between the battery tube and the the throat of the light:



It hasn't scratched my batteries so far but I am concerned about that fragment in the long term so will look to get that removed shortly.


*UI*
The light has a main foward clicky switch that serves only to turn the light on/off in momentary or "latched". All mode changes are done via the silver button on the throat of the light. This button is used only to change levels and to access the hidden strobe, it will not turn the light on/off. Depressing the button will cycle the light through L, M, H, T successively and always in that order. So let's say you are in M, upon depressing the silver button once, it will cycle to H and so on and so forth

The light has a really neat feature in that it will actually fade up or down to the next level. It's cool to see it dim quickly from Turbo to Low mode rather than the abrupt level changes I've grown accustomed to with all other lights that do not feature variable control.

Strobe is hidden and is both actived and deactivated by holding the silver button for at least two seconds. It will always come on in full blast T mode. When activating strobe, it will first cycle to the next mode but upon deactivation, it will revert back to your original mode. So let's say you were in M and you wish to activate Strobe, it will first cycle to H immediately upon the button being pressed and then will go into Strobe mode. Upon deactivating the strobe it will revert back to the original mode you were in before you activated the strobe. I tested this in all 4 modes to confirm the behavior is consistent.

The only time I kind of see this being a problem is if you were in T and for whatever reason you needed the full blast Strobe, that temporary reduction to L may not be desired and inconsistent with your need to activate strobe in the first place (unless of course it's just for show & tell).


*RUNTIME*
Edit 8/27: Mfg Claims (ANSI):




I used various rechargeable battery combo's to provide an idea of what you can expect with similar batteries that you might own. 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 as taken right before the test (only AW2600 so far)
- Actual runtime until the battery cut out (first in HR and then in M so read this as 1.3 Hrs *OR *79 Min)
- For testing on Turbo only (in which case a fan was used), temperature: ambient, the head at start and the max it reached

Axis: X = Time in Min and Y = Relative Output












My unit didn't live up to the mfg's claim (1h 50m) on Turbo. At best, I was only able to squeeze out 79m before it kicked down to High mode. I believe there was a thread mentioning that the initial batch of TK21's were affected with bad run time and that Fenix was replacing those (will post link to thread when I find it).

*EDIT 9/26*: See reply #14 for further topic about the replacement (none as this wasn't an issue). Also, in re-reading the ANSI standards, which to recap is the total runtime until light reaches 10% output from original value measured 30 seconds after light was turned on, I not only matched but exceeded ANSI claims for Turbo since the light stayed on High through about 175min on AW2600 which is just shy of 3hrs. I've added a 2nd battery/runtime stats to show the ANSI runtimes achieved.

I've also revised the runtime on Turbo since I just got in some brand new RediLast batteries rated @ 3100mAh. While it didn't help the light stay in Turbo any longer than the AW, it did extend the total runtime on H by nearly .5hr until it dropped out.
*END EDIT 9/26* 








On high I was able to exceeded mfg's claim using AW 2600's: 6.2hrs vs. 5.17hrs.

Edit 8/29
Current draw on Med and L were measured as 111mA & 13.4mA respectively on an AW2600 so on paper, this should yield 23.42H & 194H respectively.

*TINT*
Of the XM-L lights that I own (T20C, Manafont Drop-In, TK21), this is definitely the greenest tint. The hue is most evident in the corona surrounding the hotspot while whitewall hunting, however, it's also quite prominent here in this day time pic in direct sunlight for comparo:





*INDOOR BEAMSHOTS*
Edit 8/29
All shots on Canon S3 IS using WB that yields the closest to what my eyes see (left = 1/13" @ f2.7 | right = 1/80" @ f2.7)

Edit 8/30




*FNX TK21*


 



*SWM T20C*


 



*OLT M20 w/Manafont XM-L 3S Drop-In SM*


 



*DBS V2 w/Manafont XM-L 3S Drop-In SM*


 

 

*SF M3LT*


 

 

*LMP VX Ultra w/XR-E R2 & TurboForce Kit*


 

 

*SF E2DL*


 

 

*SF G2Z w/Neofab D1000*


 

 

*SF Z2 w/Malkoff M60*


 

 

*JB RRT-0 XR-E R2 SM*


 

 

*SWM V10A*
*

 

 *

*SWM V10R Ti*


 

 

*JB TCR-2*


 

 

*SF L1*


 

 

*SF E1E w/kuku427 Warm XP-G 3S Tower*


 





*NEW 10/12
OUTDOOR BEAMSHOTS
*Here are some quick outdoor shots. For full details and comparo vs. 23 other lights, please see here.
*












LONG DISTANCE OUTDOOR BEAMSHOTS
*I recently completed some long distance outdoors shots. For full details and comparo vs. other lights, see here.
*

 

 
*


*GALLERY*


 

 

 

 

 

 

 

 

 

 

 

 


 

 

 

 

 



Disclosure: The TK21 was won via a dealer contest on CPFMP. Any other items used in this review that were provided by a manufacturer/dealer have been previously disclosed in their respctive review.


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## swan (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Thanks Tim, i really like the ui on this light and the price.I hope the tint and metal fragment are one offs-marty.


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## Providence (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

the pictures look so wonderful!
i heard that the TK21 will change the mode by itself, that's quite annoy. is that true?


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## candle lamp (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Excellent review. TurboBB ! 

Thanks for your effort & very nice pictures as well.


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## siuba (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

finally got review~ thank you~
cause the runtime problem i can see many people give up this flashlight and sell it .. now no one interest at all


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## kj2 (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

"However, looking down the battery tube, I noticed some residual burr from what looks to be the mating between the battery tube and the the throat of the light"

That's one of the point what I hate of this light. It already have took of some plastic wrapping of my batteries. 

And than there is of course; the runtime on turbo. I used 4 different batteries. And 4 times, it didn't do more than 40-50min on turbo. 
It's a nice light, but when I take this thing with me, I also take at least 2 other batteries with me. 

"I believe there was a thread mentioning that the initial batch of TK21's were affected with bad run time and that Fenix was replacing those (will post link to thread when I find it)." 

-I contacted Fenix about this, and they said; That Fenix didn't have a call-back action.


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## Richub (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

My TK21 doesn't run well on 18650s, and indeed has a poor runtime on turbo. (approx. 45 mins)

These 'flaws' made me use it a lot less than I originally intended to. Pity. 
However, I decided to keep it. It's a nice pocket rocket to impress people with.


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## kj2 (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*



Richub said:


> My TK21 doesn't run well on 18650s, and indeed has a poor runtime on turbo. (approx. 45 mins)
> 
> _*These 'flaws' made me use it a lot less than I originally intended to. Pity. *_
> However, I decided to keep it. It's a nice pocket rocket to impress people with.



I feel the same


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## samgab (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Good review, cheers... "symmetrophobes". Whatever or whoever they are, I guess I'm the opposite. OCD maybe. That off-center "hot" would drive me crazy!


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## subwoofer (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Not to hijack your thread, and it is interesting to see a different review, but I posted a review of this light a couple of months ago:

http://www.candlepowerforums.com/vb/showthread.php?317515-Fenix-TK21-U2-%E2%80%93-A-review-in-four-parts

I like your runtime graphs.

The comment about the engraving being flawless even over a change in angle is because Fenix use laser engraving, so there is no tool contacting the surface. It gives a nice clean engraving. The last two Fenix lights I have got, both had the 'ash' from the engraving still on the surface which I had to wipe away.


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## CheepSteal (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*



samgab said:


> Good review, cheers... "symmetrophobes". Whatever or whoever they are, I guess I'm the opposite. OCD maybe. That off-center "hot" would drive me crazy!


 +1 I have OCD and stuff that isn't in line bugs the heck out of me. To me, symmetry or planned angles show a well thought out design and/or quality control (not saying Fenix doesn't have high QC).
That green tint looks very noticeable though, my LD20 R5 had a very green tint similar to his one. My R4 replacement has a terrible angry blue with a donut hole. In my experience, Fenix's build quality has been quite good but the LED's haven't been picked very well.


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## SkyPup (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

I've got two of them and they are my normal "Go To" lights when taking the dogs out for a walk in the woods and beaming the coyotes eyes....


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## subwoofer (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*



SkyPup said:


> I've got two of them and they are my normal "Go To" lights when taking the dogs out for a walk in the woods and beaming the coyotes eyes....


 
What do you feed them with, CR123s or 18650s?


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## turboBB (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Thx for the replies all!



swan said:


> I hope the tint and metal fragment are one offs-marty.


Apparently per the other replies, this wasn't an isolated incident (both tint and the burr).

====



Providence said:


> i heard that the TK21 will change the mode by itself, that's quite annoy. is that true?


 


siuba said:


> finally got review~ thank you~
> cause the runtime problem i can see many people give up this flashlight and sell it .. now no one interest at all


 


kj2 said:


> "And than there is of course; the runtime on turbo. I used 4 different batteries. And 4 times, it didn't do more than 40-50min on turbo. It's a nice light, but when I take this thing with me, I also take at least 2 other batteries with me.
> 
> "I believe there was a thread mentioning that the initial batch of TK21's were affected with bad run time and that Fenix was replacing those (will post link to thread when I find it)."
> 
> -I contacted Fenix about this, and they said; That Fenix didn't have a call-back action.


 
I haven't encountered random mode changes but the auto-downshift from Turbo to High mode is by design to protect the battery when it can no longer sustain the current draw in Turbo. I suppose the main point of contention here is that based on the threads I've read, no one has been able to match the stated mfg. claims of 1h 50m on Turbo. The closest I recall was 1h 33m but at 17m off, that's still a difference of around 15% less.

As for the replacement, I was a little off about that as it was isolated to a store and not through Fenix directly. Check out the replies from #65 on here:
http://www.candlepowerforums.com/vb...-user-interface-problems/page3&highlight=TK21

====



samgab said:


> Good review, cheers... "symmetrophobes". Whatever or whoever they are, I guess I'm the opposite. OCD maybe. That off-center "hot" would drive me crazy!


 


CheepSteal said:


> +1 I have OCD and stuff that isn't in line bugs the heck out of me. To me, symmetry or planned angles show a well thought out design and/or quality control (not saying Fenix doesn't have high QC).


 
I didn't know what a symmetrophobe was either before this review.  While I've come to appreciate assymetry depending on the object, it definitely doesn't work here but fortunately it's not enough to bug me either.

====

@subwoofer - That was an awesome review! Now I gotta look up some clips of laser engravings in progress. 

Cheers,
Tim


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## SkyPup (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

I am using both...


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## turboBB (Aug 23, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Photo gallery up.

Cheers


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## turboBB (Aug 27, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Some new material added as well as additional runtime on H along with all current measurements. Just search for 8/27 if you've already read the review so you can easily jump to the new stuff.

For those of you in Irene's path, stay safe (and dry!). We're just getting a taste of the beginning of her fury... :shakehead

Cheers,
Tim


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## turboBB (Aug 29, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

Indoor beamshots vs. 14 other lights added.

Cheers,
Tim


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## turboBB (Aug 29, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes)*

All lights and bats used posted (search 8/30). Unless there are any specific requests, this pretty much concludes this review. I *might* do some outdoor beamshots but will likely post it as a separate comparo thread instead of specific to this review.

Cheers,
Tim


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## PhosCosmos (Sep 12, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

I received my Fenix TK21 a couple of weeks ago and have been very happy with it. I bought a cheap Ultrafire 3000 mAh battery and didn't get but about 10 minutes of run-time on Turbo. I just finished testing the run-time using a brand new Redilast 2900 mAh battery and got 80 minutes of run-time on Turbo before it kicked down to medium. While not 110 minutes as the manufacturer specified, since I only use turbo for a few minutes at a time, this doesn't bother me. I run late at night; 5+ hours with 180 lumens output is great for me. If I need to bump to 468 lumens I can.


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## turboBB (Sep 26, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*



PhosCosmos said:


> I received my Fenix TK21 a couple of weeks ago and have been very happy with it. I bought a cheap Ultrafire 3000 mAh battery and didn't get but about 10 minutes of run-time on Turbo. I just finished testing the run-time using a brand new Redilast 2900 mAh battery and got 80 minutes of run-time on Turbo before it kicked down to medium. While not 110 minutes as the manufacturer specified, since I only use turbo for a few minutes at a time, this doesn't bother me. I run late at night; 5+ hours with 180 lumens output is great for me. If I need to bump to 468 lumens I can.


 
All,

Thx to PhosCosmos and your collective replies, it made me revisit the whole runtime "issue" with the TK21 on Turbo. In rereading mfg claims that were based on ANSI as well as the ANSI standards, I've actually bested what they have posted.

To clarify, Fenix had stated a total ANSI runtime of 1h 50min on Turbo. As per the disclaimer at the very bottom of the product page: "Notice: The above-mentioned parameters (tested in lab using quality CR123A primary lithium batteries) are approximate and may vary between flashlights, batteries, and environments."

ANSI standards for runtime is the total time until output drops to 10% of original value measured 30 seconds after the light was first turned on. My initial testing was based solely on the total time the light stayed in Turbo and not going by ANSI standards. As such, I've posted new data (just search 9/26) and added a second chart to show the ANSI numbers achieved and all of the results I initially achieved exceeds mfg claims regardless of the battery used.

As a reviewer, it's absolutely imperative that I present objective, and accurate facts and I unfortunately got caught up in focusing on the time in Turbo that I feel I have contributed to the misinformation re: the mfg's original runtime claims.

As such, I admit that I goofed here  and would like to apologize to my readers as well as Fenix. 

Hopefully this clarifies things re: the runtime.

Cheers,
Tim


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## Tenebrae (Oct 5, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

I wanted to buy the TK21, I really did. I liked the size, loved the user interface and was thoroughly satisfied with the output. Then I looked at that beam.:sick2: That green, green beam. Are all U2's like that? Admittedly, I have a preference for neutral lights but I can go with cool if they skew blue. But green? Can't do it. It's was a deal-breaker for me.


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## dheim (Oct 7, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*



Tenebrae said:


> I wanted to buy the TK21, I really did. I liked the size, loved the user interface and was thoroughly satisfied with the output. Then I looked at that beam.:sick2: That green, green beam. Are all U2's like that? Admittedly, I have a preference for neutral lights but I can go with cool if they skew blue. But green? Can't do it. It's was a deal-breaker for me.



it's not THAT green... kinda greenish, yes, but nothing you'll ever notice in real life use, anyway. it's quite warm indeed. don't be discouraged by that pic, it's an excellent little light!


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## turboBB (Oct 12, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

@Tenebrae, I agree with dheim that it's not _that _green. The outdoor shots against warm sunlight will make nearly any XM-L light in my collection look green. However if you take a look at the outdoor shots I just added (search 10/12), it's not too bad. The quick shots were not color corrected so does look greener than norm but the long distance shots are pretty accurate.

Put it this way, if your main use is indoors against white walls then yes, it'll likely bother you but outdoors and especially shining on green foliage, it would actually look a little warm.

Cheers,
Tim


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## woodrow (Oct 24, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

I have this light and like it. It is much brighter than the TK12/15. I really like the UI (hated the twist back and forth motion of the old Fenix's and Olights) and on my light, I am lucky to get a nice neutral white tint. It does need good 18650's to get the best out of it...but luckilly, I am old enough to remember putting 2x123a in my Surefire (remember when they made bright 2 cell lights) gpz with the P61 bulb every 15 minutes of runtime. Getting 3+ times the light and and 50+ minutes before you just put in another 18650 does not bug me. I think Fenix made a decent light here. Thanks for the great pics and runtime graphs. Great review!


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## madecov (Nov 6, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

This is one of the lights I purchased in my search for the perfect duty light. Not a bad light at all and I would carry it on duty if there was a decent holster for it. I hate twisty heads and figured that out after I purchased an O-Light M21X and an Eagletac T20C2. 

My TK-21 has a nice color to the beam, no burr. I have not taken it outside yet but the smooth reflector should make for a nice thrower. I actually think the TK-21 may work well as a carbine mounted light.


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## rockspider (Nov 14, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

I recently bought a TK-21 U2 and honestly cannot be more happy about it!
Let's start with the engraving, on mine it's perfectly centered between machined flats, so it's perfect for symmetrophobes also, LOL!
The holster fit tight and snugly, even when occasional running it's not bouncing too much around.
The light output is really nice, the slightly-greenish corona is visible only in the two lower levels, but in high and turbo the light is just white. Very natural colour rendition.
It's not a thrower, even if it throw not bad for the size. It has a lot of usable light spill, good for general use, but makes foreground too bright for your eyes to appreciate the actual throw. 
Cannot comment on runtime as I never use it for very long times continuos, and if I do it's on medium most of the times with short turbo burst.
Out of curiosity I carefully checked for what is described above as a "burr" in the battery tube. Upon close inspection that is not a burr but a square notch machined in the tube. Not clear what's for, but it ain't going to hurt the battery in any way.
All in all, even if the TK-21 is more a tactical than an edc, from day of bought it has become my new EDC :thumbsup:


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## Confederate (Dec 30, 2011)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

I was getting ready to buy one of these lights, but after reading your review I can only say I'm disappointed. I should be used to the fact that manufacturers pad the stats in luminosity and runtimes, but it appears that competition has caused major manufacturers (and Fenix used to be one of my favorites) to not just pad them by a few lumens and minutes, but substantially. I'm used to paying the price for brightness and runtimes; however, I'm not willing to pay increases in $$$ and guacamole tints unless I see reviews like this first. It makes me wonder if manufacturers' stats are based on anything at all. (As a former federal employee, I carefully measured stats only to see my bosses send me back to the task until more favorable ones were forthcoming. I finally just made them up, freeing up time for longer lunch breaks and a lot less grief.) 

I suppose it's one reason retailers have concocted weasel words like: "The above parameters are approximate and may vary between flashlights, batteries, and environments." 

Interestingly, manufacturers have realized that users also need very low-light modes and competition in this area is rapidly growing. I'd like to see more devoted to this aspect of new lights. Alas, as voltage decreases green tint increases, but I hope this will eventually be overcome.


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## Bojujuju (Jan 8, 2012)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

Informative review. Thanks!


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## MRTdiver (Jan 9, 2012)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*



madecov said:


> This is one of the lights I purchased in my search for the perfect duty light. Not a bad light at all and I would carry it on duty if there was a decent holster for it.


 How about a custom leather holster, maybe like THIS one? The link to his store is at the bottom.


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## finn (Jan 16, 2012)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

Reading the replies here, it seems like ANSI is a **** poor standard for measuring runtimes, and makes little sense to use on a regulated light. People are getting confused by the ANSI standard, and then assuming the manufacturer posted false runtime numbers.


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## dajab77 (Jan 17, 2012)

*Re: Fenix TK21 U2 Review (Pics, Runtimes & now w/Indoor Beamshots vs. 14 other lights*

Great review. I'm thinking about getting this light.
Thanks


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