Klarus XT10 (XM-L T6, 2xCR123A/1x18650) Review: RUNTIMES, BEAMSHOTS and more!

Originally posted: July 14, 2011
Last revised: July 21, 2011

Warning: even more pic heavy than usual.

The XT10 is part of Klarus' second set of offerings. A tactically-inspired light, the XT10 features a dual-switch tailcap interface and a revised build.


As before, packaging is fairly standard. The light comes with a good number of extras. Inside the cardboard box with plastic insert is the light, manual, spare o-rings, wrist strap, pocket clip, and belt holster (with closing flap). Also new with the XT10 is a removable grip ring.

A comment on the holster - it works well enough, as long as you don't push the light in too deeply. If you do, it can be hard to pull back out again (the concentring rings near the head seem to get caught somewhat). Also, as always, these sorts of tappered holsters work better without the grip ring installed.

From left to right: Redilast 18650, Klarus XT10, Klarus NT20, Sunwayman T20C, Fenix TK15, NiteCore IFE2, Olight M20

All weights with no batteries.

Klarus XT10: Weight 121.3g, Length: 144.8, Width (bezel) 34.9mm
Fenix TK15: Weight 131.1g, Length 147.1mm x Width (bezel) 34.0mm
Lumintop TD-15X: Weight 150.3g, Length 147.3mm, Width (bezel): 37.8mm

Overall size of the XT10 seems about typical for this class of light.

Although styling is matter of personal taste, I quite like the look of these new Klarus lights. I particularly like the rich dark grey (almost brown) color of the anodizing (type III = HA claimed) – very similar to the Sunwayman lights. No blemishes or flaws on my sample, annodizing looks to be a good thickness.

Labels are fairly small, but clearly legible against the background. I note there are distinct serial numbers on both the head and tailcap on my sample.

Knurling is not very aggressive, but there are a number of body ridge details to help with grip. Square-cut screw threads are anodized for tailcap lock-out.

The most distinctive part of the light is the dual-switch control in the tailcap. The main on/off switch is the larger, circular, protruding one (forward clicky switch, typical feel). The smaller recessed semi-circular one is an electronic mode-changing switch (slightly firmer feel than most electronic switches, definite click on activation). Both are easy to access one-handed by the thumb or index finger, in an over-hand tactical grip

Light cannot tailstand, despite the raised areas for the lanyard attachment.

I haven't shown the optional grip ring or clip-on pocket clip, but both are fairly typical in this class. Note the clip is head-facing, and not reversible. You'll need to temporarily remove the o-ring to get the grip ring on.

Although there is no spring in the head, all my flat-top high capacity cells fit and worked in the light.

Typical size head, with OP reflector, with a well-centered XM-L emitter on my sample. I would expect a balanced beam profile.

Which brings me to the white-wall beamshots. All lights are on AW protected 18650, 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. All beamshots taken immediately upon activation.

User Interface

Press the large forward clicky switch for on-off (press for momentary, click for locked-on).

Change modes by pressing the smaller electronic switch. Mode sequence is Hi – Med – Lo, in a repeating loop. Press and hold the mode-changing switch to activate Strobe.

Note that Strobe can be activated directly from Off by pressing the secondary switch. I haven't measured it, but this suggests to me that a standby current must be present when the tailcap is fully tightened.

There is no memory mode – the light always comes on in Hi mode.


Hi mode:

Med mode:

Lo mode:

Unlike the early Klarus lights, the XT10 uses PWM. Oddly, this includes the Hi mode. PWM frequency varied from 953-975 Hz. While this is detectable, it is not noticeable or disturbing in practice.

Strobe uses the oscillating format popular on "tactical" strobes lately. Strobe frequency switches between 14.8 Hz and 5.8 Hz every 2 secs. Definitely very annoying, as intended.

Interesting feature that you can directly activate it from off.

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

Throw/Output Summary Chart:

Effective November 2010, I have revised my summary tables to match with the current ANSI FL-1 standard for flashlight testing. Please see http://www.sliderule.ca/FL1.htm for a description of the terms used in these tables.

The reported 470 ANSI FL-1 lumen spec for the XT10 is very believable (my estimate is just an approximation, based on the method described in the link above). This puts the XT10 right around the typical level for most XM-L-based lights (e.g., original Thrunite Scorpion, 4Sevens X7, Skillhunt X1, etc.), but not as high as a couple of the recent heavily-driven XM-L lights (e.g., Thrunite Scorpion V2, Spark SL6).

Note however that the XT10 steps down to a lower max output after 4 mins runtime (see runtime charts below). I estimate this lower output to be around 320-350 lumens, depending on the battery source.

Throw is reasonable, and what you would expect for a reflector this size, driven at these levels.

Output/Runtime Comparison:

Note the XT10 steps down after 4 mins runtime on all batteries tested. This is becoming a more common feature on a number of lights, to protect against overheating the cells. Initial max output can be re-obtained by simply clicking the light off-on.

Runtime is reasonable for a PWM-based light at these output levels, but is of course not as efficient as current-control would be.

Potential Issues

Light uses PWM on all modes (including Hi) at a detectable, but not visually distracting ~1kHz range.

Light lacks a memory mode, and always comes on in Hi.

Flat-top cells fit and work, but my three Redilast 2600mAh cells all produced severe flickering on the Lo mode. Seems to be a specific issue with that series of cells, as there was no issue with any of my Redilast 2900mAh cells, or any of my AW cells (2200mAh, 2600mAh, IMR 1600mAh) or 4GREER cells (2400mAh).

Preliminary Observations

Beauty is always in the eye of the beholder, but I like the look and feel of the XT10. It is a solid feeling light, well balanced in the hand. I particularly like the colour and quality of the anodizing, very Sunwayman-like. I also like the more substantial body design, compared to earlier Klarus lights.

The most distinctive part of this light is the tailcap design and interface. I am not an expert on this front, but it seems to me that the XT10 has gotten this right as a "tactical" light. The light always comes on in Hi mode, and disorienting oscillating strobe is available by a single click, directly from both off and on.

The XT10 circuit uses a step-down feature after 4 mins of continuous max output, on all batteries. This is a good safety feature (to prevent over-heating of cells), and something I am starting to see more frequently in this class. I suspect some of the tactical crowd would have preferred even higher output to start with, but I find all the XM-L-based lights to be plenty bright on max.

Beam pattern is good, well-balanced for general purpose use.

I am sorry to see the current-control on the original Klarus models replaced with PWM here. Although not distracting in use, the ~1kHz PWM is detectable (and all levels, including Hi), and lowers overall efficiency somewhat. But the runtimes are still reasonably good, especially for a PWM-based light.

At the end of the day, this is another "tactically-inspired" light for you to consider in this ever-expanding class of 2xCR123A/1x1860 lights. I will have to let others with more experience on tactical use comment, but I find the rear dual-button setup to work well for single-handed use.


Klarus XT10 provided by goinggear.com for review.

To follow the online discussions for this review, please see the full review thread at CPF.

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Page last updated on July 23, 2011 - selfbuilt (at) sliderule (dot) ca (replace the "at" and "dot" labels with the appropriate symbol for e-mail)
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