# Olight M20S-X and M21-X (XM-L2, 1x18650, 2xCR123A/RCR) Review: RUNTIMES, BEAMSHOTS+



## selfbuilt (Jul 17, 2013)

*Warning: pic heavy, as usual. *











The Olight M-series lights have a long history, starting with the inaugural 1x18650, 2xCR123A/RCR M20 (XR-E R2) back in 2008. That light was updated with a XM-L U2 module a few years later, and a number of variants were produced - including the dual-switch M20S and slightly larger M21 (SST-50) and eventual M21-X (XM-L). 

Earlier this year, I reviewed the latest member of this family, the M22 (XM-L2). Since then, Olight has gone back and added XM-L2 emitters to the M20S-X and M21-X. Let's see how the latest versions of those lights compare to the modern competition. :wave:

*Manufacturer Reported Specifications:* 
(note: as always, these are simply what the manufacturer provides – scroll down to see my actual testing results). Also, see my M22 review for a spec comparison.

*Common Specs:*

LED: XM-L2 Cool White
Compatible with 2 x CR123A/RCR123 or 1x 18650 batteries
Battery polarity reverse protection
Rectangle threads, new pocket clip, as well as new position structure for cigar holder, which greatly raise its reliability
Anti-rolling cigar holder is convenient for steady holding the flashlight; and there is a 3mm diameter hole can pass through fabric strap
Aviation grade aluminum body, with anti-scratch type III hard anodizing 
Deluxe packing：Flashlight x 1; Lanyard x 1; Spare O-Rings x 2; White Diffuser x1; CR123A x 2; Holster x 1; Battery Magazine x 1; Silicon Rubber Boot (fluorescence ) x 1;
Ordinary packing：Flashlight x 1; Lanyard x 1; Spare O-Rings x 2; Battery Magazine x 1; Silicon Rubber Boot (fluorescence ) x 1;
Optional accessories (sold individually). Olight Brand CR123A Lithium Battery 3V 1500mA. OLIGHT Weapon Mount WM20. OLIGHT Magnet Weapon Mount X-WM01. OLIGHT Magnet Weapon Mount X-WM02. Stainless steel striking bezel. Traffic wand (white, orange). Filter (white, red, green, blue). Remote pressure switch.
*M20S-X (XM-L2)*

Three adjustable brightness levels: 550 lumens (1.3 h), 110 lumens (5 h), 10 lumens (85 h), and 10Hz strobe
Beam Intensity: 9,700 cd
Beam Distance: 197m
Innovative tactical user interface and dual tail switches; New UI assigns the dimmable function to tail-cap switch, which greatly facilitate tactical applications, especially via remote press switch. Tail side switch controls output brightness levels, three brightness levels “low-medium-high” changes by circle. Hold the button to activate strobe
Lock-out function: press the tail switch and side switch simultaneously, the light will power off and then locked-out.
Water resistant up to IPX7
Impact resistant up 1.5 m
Dimensions: (L) 140mm, (Head) 35.5mm, (Tube) 25mm
Weight: 124g (without battery)
MSRP: ~$70
*M21-X (XM-L2)*

Three adjustable brightness levels: 750 lumens (1.5 h), 320 lumens (3 h), 20 lumens (30 h), and 10Hz strobe
Beam Intensity: 20,700 cd
Beam Distance: 288m
Multi-functional tail switch: Under off status, lightly press the tail switch will perform momentary-on, while twice quick clicks will activate high brightness and triple quick clicks will activate strobe, further full press will acquiesce in outputs. Under on status, full press the tail switch will perform power off.
Three adjustable brightness levels (low-medium-high), changeable in cycle through screwing the head from loose to tight
Water resistant up to IPX8
Impact resistant up 2 m
Blackening treatment stainless steel striking bezel also available
Time limit high brightness steps down. After 5 minutes running, output on high will drop down to 60%. Restart the flashlight or reactivate the high brightness level to recover 
Dimensions: (L) 145.5mm, (Head) 40.2mm, (Tube) 25mm
Weight: 126.5g (without battery)
MSRP: ~$77
My samples came in the Deluxe packaging.

M20S-X













Note that the M20-X and M20S-X have identical packaging - it is the light that identifies the specific model.

M21-X













For the Deluxe packaging, each light comes in a presentation-style plastic carrying case, similar to the other M-series lights from Olight. The light and all accessories are carefully packaged in cutout foam. Included with the light is a sturdy belt holder, spare O-rings, GITD tailcap button cover, good quality lanyard, 2xCR123A battery carrier, diffuser cover, warranty card and manual.

M20S-X





M21-X:









From left to right: Eagletac Protected 3400mAh 18650; Olight M20S-X, M21-X, M22, Armytek Viking Pro v2.5, Eagletac G25C2-II.

All dimensions directly measured, and given with no batteries installed:

*Olight M20S-X:* Weight: 124.1g, Length: 145.4mm, Width: 35.5mm (head)
*Olight M21-X:* Weight: 125.5g, Length: 144.5mm, Width: 40.3mm (head)
*Olight M22*: Weight: 148.4g, Length: 144.8mm, Width: 41.2mm (bezel)

*ArmyTek Viking V2.5:* Weight: 159.8g, Length 153mm, Width (bezel): 39.5mm
*ArmyTek Viking Pro V2.5:* Weight: 161.9g, Length 152mm, Width (bezel): 39.5mm
*Nitecore SRT7*: Weight: 172.4g, Length: 158mm, Width (bezel): 40.0m
*Eagletac G25C2-II* (stock): Weight 141.0g, Length: 150.6mm, Width: 39.6mm
*Eagletac TX25C2*: Weight 93.6g, Length: 120.4mm, Width (bezel): 31.6mm

Overall dimensions for the M20/M21/M22 class are similar – except for the larger bezel diameters as you go up in model numbers. Overall, they are very similar to other lights in this class.










M20S-X:













M21-X:













Physically, the build of these lights are similar to the other lights in the M-series, with generally common external styling of the body handle and tailcap. Anodizing is a matte finish now (previously glossy black on the early models), but remains hard anodized (i.e., type III). Body labels remain bright and clear, and are sharp against the black background.

As before, these lights don't use knurling per se – instead, the trademark Olight raised checkered pattern is used over the battery tube and tailcap to help with grip. It does fairly well, but is not as "grippy" as aggressive knurling. With the metal grip ring and clip installed, I would definitely consider grip to be above average for the class.

One thing that has changed is screw threading – the new M20S-X and M21-X feature square-cut threads (of good quality), just like the recent M22. These are anodized at the tailcap to allow for lock-out, on either light. :thumbsup:

As before, there is a spring mounted on the positive contact board in the head, so flat-top cells can be used in the light. 

The bundled cigar grip ring is made of metal, and has a groove that fits into a slightly raised piece of metal by the removal clip (which helps hold the grip ring in place). There is a hole in the grip ring to let you thread a lanyard strap through.

Due to the forward physical clicky switch, neither light can tailstand. 

The main physical difference between the lights is the larger head on the M21-X (although still smaller than the M22), and the secondary mode switch on the tailcap of the M20S-X. This is an electronic side-switch, under a blue cover. Switch feel is typical for an electronic switch. Scroll down for a discussion of the user interfaces.






The holster remains a distinctive item in the package. There is a hole in the bottom (so you can tell if the light is on), and space to carry two extra 18650 cells (or carriers with 2xCR123 each).

I also quite like the standard Olight diffuser covers (included in the deluxe packaging), which fit snuggly over the head of the lights. Olight diffusers are of high quality, and can generally be used on many other lights of similar bezel size (thanks to the somewhat stretchy rubber cover).

Both my samples came with black stainless steel bezels, although I believe shiny metal finish is also available. Let's take a closer look at the heads:

M20S-X:









M21-X:









Reflectors are smooth on both my samples (larger on the M21-X, of course). XM-L2 emitters (Cool White) were well centered on both. Scroll down for beamshot comparisons.

*User Interface*

_M20S-X_

The M20S-X interface has been slightly updated from the original M20S.

As before, turn the light on/off by the tailcap forward clicky switch (press for momentary, click for locked-on). Doing a double-click/double-press of the tailcap switch jumps you to Hi, and a triple-click/triple-press of the switch jumps you to Strobe. 

There are three main output levels controlled by clicking the side tailcap switch (electronic switch under the blue cover). From On, mode sequence is Lo > Med > Hi, in a repeating loop. The light has mode memory, and retains the last level set when you turn it off on. 

There is a Strobe mode available by pressing-and-holding the side switch at any time – including from Off. This indicates that there is a standby current at all times when the light is connected.

To lock out the light, press and release both tail buttons simultaneously. Repeat this maneuver to unlock the light.

_M21-X_

User interface has been updated slightly from the original M21, and is identical to the recent M22.

As before, turn the light on/off by the tailcap forward clicky switch (press for momentary, click for locked-on). Doing a double-click/double-press of the tailcap switch jumps you to Hi, and a triple-click/triple-press of the switch jumps you to Strobe. 

There are three main output levels controlled by a loosen/tighten of the head. Mode sequence is Lo > Med > Hi, in a repeating loop. The light has mode memory, and retains the last level set when you turn it off on.

The main difference from the original M21 is the presence of these extra multiple click options now, with Strobe having been removed from the main sequence (i.e., is now "hidden"). There is no memory for the special multiple-click states of the light. 

*Video*: 

For information on both the M20S-X and M21-X lights, including the build and user interface, please see my video overview:



Video was recorded in 720p, but YouTube typically defaults to 360p. Once the video is running, you can click on the configuration settings icon and select the higher 480p to 720p options. You can also run full-screen. 

As with all my videos, I recommend you have annotations turned on. I commonly update the commentary with additional information or clarifications before publicly releasing the video.

*PWM/Strobe*

_M20S-X:_

Like the original M20S, Pulse Width Modulation (PWM) has to be used to support the dual-switch option. Apparently, this is required to synchronize the dual circuits (i.e., one in the tail, one in the head). All the other M-series Olight lights are current-controlled.

PWM Lo





PWM Med





PWM Hi





As you can see, on the M20S-X, PWM is of a constant frequency of 1.157 kHz. The duty cycle (i.e., on-off phase) depends of the apparent intensity of the light. Unlike many lights though, PWM is still present on Max output here. Again, I understand this is required for circuit synchronization.

In any case, the 1.157 kHz is fairly acceptable in practice, in my view. I am particularly sensitive to PWM flicker, and I don't find these sorts of >1 kHz frequencies too bad. But it is still detectable to my eye. :shrug:

Lo mode noise:





In addition to the PWM signal, there is also a secondary pattern detectable on the Lo mode. This is not uncommon on a number of PWM-based lights.

Strobe:





M20S-X Strobe was a fast "tactical" strobe, of 12 Hz frequency.

_M21-X:_

Like the M20, older M21, and current M22, there is no sign of PWM at any output level – The M21-X is current-controlled like its predecessors.  






The M21-X strobe is also a fairly typical fast "tactical" strobe, of 10 Hz frequency (as with my recent M22).

*Standby Current*

Because the electronic side switch on the M20S-X can activate Strobe even the when the light is turned off at the main clicky switch, there must be an standby current drain when the light is fully connected.

I have measured this M20S-X current as 64uA on a 1x18650. Given a typical 2600mAh 18650, that would translate into over 4.6 years before a fully charged battery would be drained. This is a negligible standby drain. 

To lock-out the light, I recommend you twist the tailcap a quarter turn. This physically locks out the light, to prevent accidental activation and remove any drain. Alternatively, Olight provides a "soft lock-out" option to prevent unwanted activation. To electronically lock-out the light, press and release both switches simultaneously (repeat to unlock the light). Presumably this lowers the standby current even further, but I haven't measured it.

Note that there is no standby current on the M21-X.

*Beamshots:*

For white-wall beamshots below, all lights are on Max output on an AW protected 18650 battery. Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences (but there may still be some variation).





























































As you can see, overall output and throw is definitely the lowest on the M20S-X (and the spillbeam width is narrower). The M21-X is intermediate to the M20S-X and M22, also as expected. Scroll down to see detailed measurement results.

*Testing Method:* 

All my output numbers are relative for my home-made light box setup, a la Quickbeam's flashlightreviews.com method. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.

I have devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt's Lightbox values to Lumens thread for more info. 

*Throw/Output Summary Chart:*

My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see http://www.flashlightreviews.ca/FL1.htm for a discussion, and a description of all the terms used in these tables. Effective July 2012, I have updated all my Peak Intensity/Beam Distance measures with a NIST-certified Extech EA31 lightmeter (orange highlights).
















There is a very clear range of max outputs and throw across the M-series line. The original M20 XM-L was relatively low-output (and throw) for this class, even at the time of launch. The M20S-X, M21-X and M22-X span the max output and throw ranges for the current 1x18650, 2xCR123A/RCR class. Basically, you get what you would expect in max output and throw as you go up in size. 

How do my lumen estimates compare across the various levels?






As you can see, my results are fairly consistent across the board with Olight's ANSI FL-1 lumens. I had a similar experience with the M22.

*Output/Runtime Graphs:*

_Note: Unless otherwise stated, all my 18650 runtimes below are based on AW 2200mAh Protected 18650 cells._




















For the M20S-X, the first observation is that it doesn't have a timed step-down feature on Max, as the M21-X and M22 do. This is understandable, given that it is not driven as hard on Max. The second observation is that the M20S-X is only semi-regulated on 1x18650 (i.e., it looks a lot like direct-drive, at all levels). There also seems to be some loss of relative efficiency on all levels due to the PWM, but it is still quite acceptable for the class (i.e., not as high as the current-controlled M21-X or M22, but still very good).

The M21-X looks like a slightly lower Max output version of the M22 (which is basically what it is). 

*Potential Issues*

The M20S-X has visible PWM on all modes, but at an acceptable >1 kHz level.

There is standby drain on the M20S-X when the fully connected, but this is negligible in my testing (i.e., would take 5 years to drain a typical 18650). You can easily lock out the light and break this current by a quarter turn of the tailcap. There is also an electronic lock-out available as well.

For the M20-X, loosen-tighten heat twists are required to change output modes.

*Preliminary Observations*

I'm glad to see Olight has "refreshed" the M20S-X and M21-X with the latest XM-L2 emitters. This will give you a small bump in output and/or runtime efficiency (depending on the specific drive level).  But it has also gives me a chance to compare the full range of Olight offerings in the 1x18650, 2xCR123A/RCR class (i.e., allows comparison to my recent M22 sample).

Physically, the M-series lights look similar to one another. Styling is virtually identical across the series (although the M22 has a redesigned head with more prominent fins). While the appearance may look similar to the early M20/M20S, there have been continual build improvements along the way (e.g., square-cut threads, revised pocket clip/grip ring, smooth reflectors). 

Output modes are easily accessible; the base M-series lights (i.e., M20, M21, M22) all use a head-twist interface, and the "special operations" M20S versions have a secondary electronic switch on the tail cap. As a result, the M20S versions have to use Pulse Width Modulation (PWM) for output level control, but this is at an improved PWM frequency (i.e., now >1 kHz). The rest of the M-series line is current-controlled, with excellent efficiency and regulation. 

I'm also glad to see that all the current M-series lights have Strobe mode either "hidden" away (i.e., off the main sequence with multiple clicks required), or assigned to the secondary switch (M20S-X). And it's a nice touch on all models to have the Hi mode available at any time by a simple double-click of the main switch. 

The deluxe presentation package remains high quality, with a lot of good extras like the decent holster and excellent diffuser cover. You can save a bit more if you opt for basic packaging, but I always recommend a good diffuser (and the Olight model is a personal favorite). :thumbsup:

In terms of deciding between the models, it really comes down to how much max output you want (and how much throw). As you go up in relative head size across the M-series, both of these features increase. Of course, there is a runtime penalty to be paid for increased max output, so I suggest you carefully balance your personal needs. As someone who "came of age" when ~100 lumen lights were first hitting the market, I find all of the M-series lights more than bright enough for general use. 

And on that note, I am glad to see that Olight's lumen and throw specs seem pretty accurate across the whole M-series line. 

While the M-series lights may not have all the "bells-and-whistles" of more complex lights in the 1x18650. 2xCR123A/RCR class, there is certainly a lot of options to choose from here. Given the performance, feature sets, and prices across this line, I expect many could find something to suit themselves here. :wave:

----

M20S-X and M21-X were provided by Olight for this review.


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## Lou Minescence (Jul 17, 2013)

*Olight M20S-X and M21-X (XM-L2, 1x18650, 2xCR123A/RCR) Review: RUNTIMES, BEAMSH*

Another great review.
Finally an answer to a question I've posted on CPF many times. Do the newer M20s lights have PWM. It's visible on my R5 emitter version. I've held off buying any of the upgraded versions since. My guess is it is not very visible to most owners because no one ever posted a reply to my posts.
Selfbuilts testing has revealed this light does have PWM. Thanks again for a thorough review.


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## whatswrongwithmee (Jul 17, 2013)

*Re: Olight M20S-X and M21-X (XM-L2, 1x18650, 2xCR123A/RCR) Review: RUNTIMES, BEAMSH*

I have the "older" M21X, it has a textured reflector and loose-tighten to change modes. This new one has a few things I do like, like more output but I prefer the textured reflector more, makes a beautiful clean beam. Also like the new mode changing more, faster and easier. Do they offer a shiny bezel? I don't like it all black too much. 

Great review as always too.


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## selfbuilt (Jul 17, 2013)

*Re: Olight M20S-X and M21-X (XM-L2, 1x18650, 2xCR123A/RCR) Review: RUNTIMES, BEAMSH*



Lou Minescence said:


> Finally an answer to a question I've posted on CPF many times. Do the newer M20s lights have PWM. It's visible on my R5 emitter version. I've held off buying any of the upgraded versions since. My guess is it is not very visible to most owners because no one ever posted a reply to my posts.
> Selfbuilts testing has revealed this light does have PWM. Thanks again for a thorough review.


Yes, it is definitely there (on all modes), and is definitely PWM. I know the frequency has improved over time, and I find the current >1 kHz frequency acceptable. And many people may not even be able to see it (I find my own perception of PWM disappears somewhere in the 2-3 kHz range).

I am not sure what the PWM freq was on the XP-G R5 versions of the M20S. I know the first dual switch tailcap Olight came out with (on the inaugural M30) was a cringe-inducing 100 Hz. I presume it had improved by the time the M20S came out, but I don't know what the progression was over time in the evolution of this model.



whatswrongwithmee said:


> Do they offer a shiny bezel? I don't like it all black too much.


According to the Olight website, a shiny stainless steel bezel is an optional accessory. Not sure who stocks it though, or what exactly it looks like.


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## phantom23 (Jul 17, 2013)

selfbuilt;4245401[B said:


> ][/B]Output modes are *well spaced *across all the models, and easily accessible.


Well spaced? Mode spacing in M21-X is rubbish! Both low and medium are at least 2x too bright. Only M20S-X has well spaced modes.


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## selfbuilt (Jul 17, 2013)

phantom23 said:


> Well spaced? Mode spacing in M21-X is rubbish! Both low and medium are at least 2x too bright. Only M20S-X has well spaced modes.


Fair enough, I was thinking more of the M20S-X when I wrote that. It's true that the M21-X (and by extension, M22) could use a lower Med mode, especially. I'll revise that comment.


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## selfbuilt (Jul 18, 2013)

In response to a question I received on YouTube - are the parts inter-changeable?

Physically yes, the heads and tailcaps are swapable. But there's no point in doing this (and good reason not to try). The M21-X tail on the M20S-X head will turn the light into a single mode only (plus strobe), while the M20S-X tail with the M21-X could lead to circuit damage (i.e., I don't know how the M21-X head circuit would react to the PWM-tail circuit).


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## cire0309 (Aug 17, 2013)

Are the cigar rings on the XM-L2 M21 and M20 the same as the M22? By this I mean that they're not threaded like the original M21.

I have the original M21 and I was thinking about getting one of the XM-L2 lights, but the M21 had a ring which covered the area when the cigar ring is removed.


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## selfbuilt (Aug 18, 2013)

cire0309 said:


> Are the cigar rings on the XM-L2 M21 and M20 the same as the M22? By this I mean that they're not threaded like the original M21.


That's right, the M20X and M21X are like the M22 - the grip rings are not threaded.


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## whatswrongwithmee (Sep 1, 2013)

Man, I brought the 600 lumen version of the M21x just 4 months ago and I can't help but get the 750 lumen version to quench my thirst for lumens. Olight better not upgrade it again for at least a year or so.


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## selfbuilt (Sep 2, 2013)

whatswrongwithmee said:


> Man, I brought the 600 lumen version of the M21x just 4 months ago and I can't help but get the 750 lumen version to quench my thirst for lumens. Olight better not upgrade it again for at least a year or so.


Well, I really doubt you'd notice the difference between 600 and 750 lumens in practice (assuming those specs on the older model were accurate).


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## whatswrongwithmee (Sep 5, 2013)

selfbuilt said:


> Well, I really doubt you'd notice the difference between 600 and 750 lumens in practice (assuming those specs on the older model were accurate).



Well, 1 meter away from the wall I can notice a difference but anymore than that it pretty much looks exactly the same. The new interface is great! Also swapped the shiny bezel off the "old" one onto the new one because that all black just doesn't do it for me.


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## zs&tas (Jun 4, 2014)

Hey, just having another browse  i was wondering if you could explain why in the tables the M21 has less output but more throw than the M22 ? i am figuring of course they are similar sizes and reflectors. seems strange ??
thanks Mr SB


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## zs&tas (Jun 4, 2014)

HaHa after writting the above i had a knock knock at the door, hello Mr Postman and a new M20s L2  
it is worth mentioning to others that the newer blue switch is much more raised and easier to find than the older models (white switch) however at this moment it also requires more pressure to use.
just a quick comparison to my M20s G2


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## selfbuilt (Jun 4, 2014)

zs&tas said:


> Hey, just having another browse  i was wondering if you could explain why in the tables the M21 has less output but more throw than the M22 ? i am figuring of course they are similar sizes and reflectors. seems strange ??


It is presumably just subtle focusing differences between my two samples. On average, I would expect the M22 to have marginally better throw than the M21 (due to the slightly higher output with similarly sized reflector). But the exact positioning of the reflector on any given sample can influence that up and down.


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## kj2 (Jun 5, 2014)




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## zs&tas (Jun 5, 2014)

haha frigin awesome man .


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## WarRaven (Aug 5, 2015)

I just ordered a M21X l2, couldn't argue with price. Seems a performer just the M22.
Late thanks for the review to get the goods on.

+1


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## WarRaven (Aug 12, 2015)

My M21X L2 arrived, strong little light.
Odd that it has different glass then my M22, it has no AR coating.

With that said, there's an obvious tint thing going on with new AR glass on the M22. The beam is colored with the AR glass, and its obvious next to the warrior without AR glass.
I like the untinted cool white of the older M21X over the newer AR glass M22.
I'm surprised this went unnoticed or mentioned.


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## selfbuilt (Aug 12, 2015)

WarRaven said:


> With that said, there's an obvious tint thing going on with new AR glass on the M22. The beam is colored with the AR glass, and its obvious next to the warrior without AR glass.


Given tint differences with emitters, you would really need to play with swapping lens in front of the emitter of each light to know for sure. There was a time on S-series lights when the heavy AR tint introduced some green-tinting, but this was corrected on the later versions. Odd to hear of a lack of tint on a recent M21X.


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## WarRaven (Aug 12, 2015)

Yes sir, I'll try and get pictures later.
I don't know if it's completely void of AR, 
though the pinkish hue is nearly absent entirely. 
On M22, it's visibly seen.
This looks like lenses on S10Rs, etc, clear looking.


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## WarRaven (Aug 13, 2015)

Sorry about quality, hopefully you can see some difference in these?






It's pretty apparent in person.


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