Klarus GL5 Foregrip Light


Brand/model Klarus GL5
LED Cree XP-L2 HD V6 6500K
Maximum lumens 1,200 lm
Maximum beam intensity 18,320 cd
Maximum throw 270 m
Battery 1*18650 Li-ion, 2*CR123A
Onboard charging No.
Material Aluminium
Modes 3
Blinkies Strobe
Reflector Smooth
Waterproof IPX8
Review date July 2022


It has been exciting to test the Klarus GL5 Foregrip Light! This is the first time that I have used a vertical foregrip on a rifle. The quality and ease of use has made this a wonderful introduction to the world of vertical foregrips.

Klarus has been around since 2011 and do their own R&D and manufacturing. They are known for their dual-switch tactical torches and supply law enforcement, military and outdoor enthusiasts.

liteshop.com.au kindly provided this Klarus GL5 Foregrip Light for review along with the Klarus GL4 Rail Light. I have not been paid for this review nor have I held back my opinions.


The Klarus GL5 came in a sturdy white retail box with a picture of the torch on the front and specifications on the sides.

Klarus GL5 packaging front Klarus GL5 packaging back
Klarus GL5 packaging left Klarus GL5 packaging right
Klarus GL5 packaging tray

The following was included in the box:

  • Klarus GL5 Vertical-Grip Light
  • 2 x Panasonic CR123A
  • 1 x O-ring
  • User manual

The spare o-ring and user manual were hidden under the tray.

Klarus GL5 accessories

Torch in use

I attached a swivel stud to picatinny rail adapter to a rifle so that the Klarus GL5 could be attached. The adapter that I used was not very adjustable so the torch was fixed at an angle that pointed slightly up.

Rifles with a chassis system and rails allow this torch to sit parallel with the barrel. These types of rifles are more commonly used by law enforcement and the military rather than by hunters in Australia.

The Klarus GL5 has a thumb screw to clamp the torch onto a rail. The lack of quick release gives me confidence that torch will remain attached.

The grip is thick and comfortable to hold and the two buttons also have a lot of grip when pressing them.

The torch can tailstand and does not easily fall over.

Klarus GL5 in use 1 Klarus GL5 in use 2 Klarus GL5 in use 3

Build quality

The Klarus GL5 has a lightweight aluminium body with a matte black finish and a rubber grip. There are no sharp edges around the grip but the corners could be made smoother so that they do not dig into my index finger or thumb when pressing buttons or strangling the grip.

The base of the grip has a battery symbol to indicate that batteries must be inserted with the negative end going in first. I found it a bit unconvential to insert a battery in this direction after having inserted a battery with the positive end facing the head in all my other torches. There appears to be reverse polarity protection because I made the mistake of inserting a battery the wrong way a few times and the torch continued to work after changing the direction of the battery.

Threads for tailcap came lightly lubricated with grease. The tailcap turns smoothly, has knurling to add extra grip and it is fun to turn.

Klarus GL5 front 1 Klarus GL5 front 2

Klarus GL5 left Klarus GL5 right

Klarus GL5 back Klarus GL5 rail attachment

Klarus GL5 buttons Klarus GL5 threads

Klarus GL5 tailcap spring Klarus GL5 tail threads

LED, bezel, lens, reflector and beam

The Klarus GL5 has one Cree XP-L2 HD V6 6500K LED with a smooth reflector.

The tube around the reflector extends into a small strike bezel to give the torch a tactical look and feel.

The glass lens does not appear to have an anti-reflective coating.

There is so much tint shift, as you would expect with a Cree XP-L2 6500K LED. The beam has a green corona and a purple halo around the spill.

Klarus GL5 emitter

I have taken Correlated Colour Temperature (CCT) and Colour Rendering Index (CRI, RA of R1-R8) measurements with the GL5 positioned one metre away from an Opple Light Master Pro III (G3).

The CCT measured ranged from about 6000K to 7500K and the CRI is about 70.

The Delta u, v is slightly positive and the tint looks slightly green on Low and Medium modes. It is closer to pure white on High.

Mode CCT (K) CRI (Ra) x y Duv
Low 6122 69.4 0.3189 0.3411 0.0063
Medium 5755 69.9 0.3265 0.3471 0.0057
High 7461 73.8 0.3015 0.3072 -0.0023

Calculate Duv from CIE 1931 xy coordinates



I took the following measurements using digital callipers.

Measurement Unit (mm)
Torch height 140.6
Torch length 78.7
Head width 35.2
Bezel diameter 34.5
Tube diameter 37.3


I took the following measurements using a digital scale.

Weight Unit (g)
Torch with battery (18650) 331.9
Torch 286.2
Battery (18650) 45.7

User interface and driver

The Klarus GL5 has a tactical user interface with High, Medium, Low and Strobe modes.

State Action Result
Off Click Main switch On (High)
Off Hold Mode switch Momentary Strobe
Off Hold Mode switch for 2 seconds Strobe
On Click Main switch Off
On Click Mode switch Cycle (High, Medium, Low)

Low voltage protection

There does not appear to be Low Voltage Protection. I let the Klarus GL5 run for five days on High and the 18650 battery voltage went down to 2.22V. I turned the torch off so that the battery would not be damaged. I would expect LVP to switch the torch off automatically at 2.5-2.7V if present.

Light output is significantly reduced when the battery is low. This is a good indication that the CR123A batteries should be replaced or an 18650 Li-ion battery should be recharged. The battery might go dead if you accidentally leave the torch running for days and it may not be safe to recharge an 18650 Li-ion battery that has gone below 2V.


I did not notice any visible PWM (flickering) for Low and Medium modes. However, the Intelligent Thermal Protection System caused the light output to go up and down within the first thirty minutes of using the High mode.

What I like about the UI

  • Direct access to High.
  • Direct access to Strobe.

What could be improved

  • I personally like the user interface as it is for tactical purposes.

Batteries and charging


Two Panasonic CR123A batteries were included inside the torch. The batteries each arrived with a voltage of 3.24V and were isolated with a plastic tab.

I was able to use 2x CR123A, 1x Unprotected flat top 18650 and 1x Protected button top 18650 in the Klarus GL5.

I used a Samsung 30Q 18650 Li-ion battery for testing, except for a High runtime test where I used the two included CR123A batteries.

Klarus GL5 batteries Klarus GL5 batteries

Klarus GL5 batteries


There is no built-in charging. This torch is intended for law enforcement where two CR123A batteries may be used and disposed of. A rechargeable 18650 Li-ion battery can be used, but you will need an external charger for it.


Specifications from the manual:

Battery Category High Medium Low Strobe
18650 Li-ion Output (lm) 1,200 500 100 1,200
18650 Li-ion^ Runtime (h) 1 2 13 2
18650 Li-ion Candela (cd) 18,320 9,375 1,849
18650 Li-ion Range (m) 270 193 86
2xCR123A Output (lm) 1,000 500 100 1,000
2xCR123A Runtime (h) 40min 1.2 8 1.3
2xCR123A Candela (cd) 14,900 9,375 1,849
2xCR123A Range (m) 255 193 86

^A 2600mAh 18650 Li-ion battery was used for runtime testing by Klarus.

Lux Meter: UNI-T UT383BT
DMM: UNI-T UT139C has been used to measure current under 10A.

Lumen measurements

Mode Amps at start Specs Lumens @turn on Lumens @30 sec Lumens @10 min
Low 0.17 A 100 lm 122 lm 122 lm 121 lm
Medium 1.14 A 500 lm 631 lm 625 lm 605 lm
High 3.89 A 1200 lm 1318 lm 1269 lm 1074 lm

Standby drain

22.8 µA.

Runtime graphs

I built a lumen tube and forked bmengineer’s project RuTiTe to add support for a VEML7700 light sensor and MCP9808 temperature sensor with help from Owen. Calibration lights from maukka were used.

Note: Lumen measurements may be off by more than 10% with my DIY lumen tube.

Klarus GL5 runtime graph

Klarus GL5 first 10 minutes runtime graph

Klarus GL5 High 18650 vs CR123A runtime graph

Klarus GL5 High CR123A runtime graph

Klarus GL5 High Samsung 30Q runtime graph

Klarus GL5 Medium runtime graph

Klarus GL5 Low runtime graph

I charged the included battery to 4.19V in an external charger before each runtime test.

I stopped recording at 2 hours for High, 4 hours for Medium and 14 hours for Low. The torch kept running with a very low output. There does not appear to be Low Voltage Protection where the torch turns off when a low voltage has been reached.

High (2x CR123A) started at 1072 lumens, quickly dropped to 615 lumens at 1 minute 30 seconds, maintained around 600 lumens for just over an hour before stepping down to 38 lumens. The maximum of 1072 lumens is similar to the specifications (1000 lumens) and the runtime of just over an hour exceeds the specifications (40 minutes).

High (18650) started at 1318 lumens, dropped to around 900 lumens within 15 minutes, maintained around 900 lumens for almost an hour, and gradually dropped off to less than 150 lumens by 1 hour 30 minutes.The maximum of 1318 lumens exceeds the specifications (1200 lumens) and the runtime is similar to the specifications (1 hour).

Medium (18650) started at 631 lumens, maintained around 590 lumens for 2 hours 15 minutes, and gradually dropped down to less than 100 lumens by 2 hours 38 minutes. The maximum of 631 lumens is slightly higher than the specifications (500 lumens) and the runtime slightly exceeds the specifications (2 hours).

Low (18650) started at 122 lumens and maintained over 116 lumens for 14 hours. I stopped recording at 14 hours. The maximum of 122 lumens is slightly higher than the specifications (100 lumens) and the runtime slightly exceeds the specifications (13 hours).

Klarus used an 18650 2600mAh battery for runtime tests while I used a Samsung 30Q 18650 3000mAh with a bit more capacity. My runtime measurements are slightly better with a higher capacity battery.

I would love to see Klarus add a breakdown of the runtime in their future specifications so that people can see how High steps down over time rather than assuming that it might last for 1 hours at 1,200 lumens. For example: 1200-900 lm, 3min-57min.


I took lux measurements with a UT383BT at 30 seconds for each mode. Each mode was measured at five metres.

Mode Specs (cd) Specs (m) Candela measured (cd) Distance (m)
Low 1,849 86 2,150 92
Medium 9,375 193 12,300 221
High 18,320 270 29,675 344


5000K WB, f3.2, 3.2" shutter speed, ISO 100

Klarus GL5 Low beamshot

Klarus GL5 Medium beamshot

Klarus GL5 High beamshot


The Klarus GL5 Foregrip Light is comfortable and easy to use. The runtime for Medium and Low is pretty good. You may want to replace the two CR123A batteries after using the torch on High for an hour. I prefer the extra runtime that you get with an 18650 Li-on battery.

Light output appears to be well regulated until the temperature hits a threshold. It would be nice if the Intelligent Thermal Protection System gradually changed the light output. Currently it reduces and increases the light output every thirty seconds when a temperature threshold has been passed.

This vertical foregrip torch is better than I expected and I am now considering getting a rifle with a chassis system so that I can properly mount it parallel to the barrel.

Thank you liteshop.com.au for providing the Klarus GL5 for review!


  • Excellent build quality.
  • Comfortable to hold.
  • Easy to use.
  • Good runtime.


  • Low Voltage Protection appears to be missing.
  • Thermal Regulation.

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