With the light switched on, rotate the toggle switch to the middle position to lock the chosen
output level, at this time, the tactical switch does not work and the output levels can not be
selected.
With the light switched off, rotate the toggle switch to the middle position to lock the tactical tail
switch, at this time, the tactical tail switch does not work and the light can not be turned on.
Unlock
Rotate the toggle switch to Tactical mode OR Duty mode to unlock the light.
Battery Specifications
Type
Dimension
Nominal
Voltage
Usability
Fenix ARB- L21-5000U
21700
3.6V
Recommended
√√
Fenix ARB- L21-5000 V2.0
21700
3.6V
Recommended
√√
Fenix ARB- L21-4000P
21700
3.6V
Recommended
√√
Rechargeable battery (Li-ion)
21700
3.6V
Banned
×
Warning: *21700 Li-ion batteries are powerful cells designed for commercial applications and
must be treated with caution and handled with care. Only use quality batteries with circuit
protection will reduce the potential for combustion or explosion; but cell damage or short
circuiting are potential risks the user assumes.
Battery Replacement
Unscrew the tail cap to insert the battery with the anode side (+) towards the light head, then
screw the tail cap back on.
Intelligent Overheat Protection
The light will accumulate a lot of heat when used on higher output levels for extended periods.
When the light reaches a temperature of 60°C or above, the light will automatically step down a
few lumens to reduce the temperature. When the temperature drops below 60°C, it will then
