OLight M31 Triton

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OLight was the first to use the Luminus leds in a production light (M20 Ti) and have continue making high power lights with it. M31 is a tactical light with high light output and very good throw. It uses the same user interface as M20 and M21 with a on/off tail switch and mode change requires a twist loose, twist tight of the head. The modes are also the same: 3 brightness settings and a strobe. The light is made of aluminum with hard-anodized (Type 3) finish.

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The light is supplied in a plastic case together with a few accessories.


The contents of the box are: The light with extender, a holster, a battery magazine for 3xCR123, 2 spare o-rings and the manual.

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From the front the big smooth reflector with the SST-50 in the center can be seen.


Just behind the reflector the light has a heatsink, but according to the documentation it is a bit small for the light (The documentation warns against running to long time in high). The light can run more than 10 minutes before it gets really hot, using it in cold weather or stormy weather will increase the cooling significant.

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Between the head and the body of the light, is the connection used for the twist of the head part of the user interface. This connection only has one o-ring. The connection to the battery plus pole has a spring this makes it possible to use flattop batteries.


On the body of the light is square knurling, this knurling is rounded.

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On the body is mounted a optional clip. When using the light with 3xCR123 or 2x18500 batteries, it has a good placement, but with 4xCR123 or 2x18650 it is on the middle of the light.


The light includes a battery tube, that can be preloaded with 3xCR123 batteries, making it fast to replace the batteries. This can only be used for the short configuration. The batteries fits tight in the tube, making it slow to reload a battery tube.
The light can easily use CR123 batteries without the tube!

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The rear end of the body has two o-rings, both the battery tube and the extender tube is equipped with the two o-rings.

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In the tail the spring is hidden beneath a cap. The switch is a forward switch, which is placed below the teeth on the tail, making it possible for the light to tail stand on plane surfaces.


This is how far I could take the light apart without tools.


The light includes a holster that can be used with both the short and long configuration of the light.

This light is a powerful thrower that is designed to supplement the M20/M21/M30 series of light with a super thrower. The light does that, but you have to watch the battery configuration, 3xCR123 is not really a good option for this light, but with two 18650 batteries the light works very well.

Technical specification and measurements


The light can be used with 3xCR123, 4xCR123 and 2x18650 batteries (2x18500 is also a possibility).

Measured size and weight:
Length: short: 212 mm, long: 246 mm
Diameter: 24 to 63 mm
Weight: 3xCR123: 307.6 gram, 4xCR123: 341.2 gram, 2x18650: 368.9 gram

The light uses a Luminus SST-50 led


In the above table I have used 2600mAh 18650 batteries for measuring and estimating runtime. The specified level spacing matches nicely up with the measured brightness.


A voltage scan shows that the light has very good regulation down to around 6 volt. The driver is rather hard on CR123 batteries around 6 volt with about 3 ampere current draw.


The light has a very fine regulation on 18650 batteries and also a good runtime, but 3xCR123 batteries do not really work in the light, at least not on high.


The light has a strobe of 9.7 Hz with 50% duty cycle, the strobe is slightly brighter than the usual high level (the green line).

Comparison to other Flashlights

Fenix TK40, Fenix TK45, OLight M31
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JetBeam RRT-3, JetBeam M2S, ThruNite Catapult V2
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For the full comparison to other lights with graphs and beamshots see here.