On/off
Press and hold either of the two switches for 0.5 seconds to turn on/off the lamp. 

Mode switching
With the lamp switched off, press and hold either of the two switches for 0.5 seconds to reach the corresponding mode.

White light mode and warm light mode cannot be operated at the same time.

Press and hold either of the two switches for 1.2 seconds to enter the SOS mode.

*In SOS mode, press and hold the white light switch for 1.2 seconds to shift to the Low output of white light mode.

In SOS mode, press and hold the warm white light switch for 1.2 seconds to shift to the Eco output of warm white light mode.

Output selection
White light mode: with the lamp switched on, single click the white light switch to cycle through Low→Med→High.

Warm white light mode: with the lamp switched on, single click the warm white light switch to cycle through Eco→Low→Med→High.

In white light mode, single click the warm white light switch to shift to the Eco output of warm white light mode.

In warm white light mode, single click the white light switch to shift to the Low output of white light mode.

Lockout Function
Lock: With the lamp switched off, simultaneously press and hold the two switches for 3 seconds, the lamp will blink 4 times on the Eco output of warm white light mode to indicate locked status.

Unlock: With the lamp locked, simultaneously press the two switches for 3 seconds, the lamp will be activated with 4 blinks and activates on the Eco output of warm white light mode. 

In locked status, clicking or pressing the switches will activate 4 blinks on the Eco output of warm white light mode to indicate locked status.

*When the charging cable is plugged in, the lamp unlocks automatically in switched-off status.

Charging
Adjust the headlamp to reveal the charging port on the back. Uncover the anti-dust cap and plug the USB Type-C side of the charging cable into the charging port of the lamp.With the headlamp switched off, the normal charging time of the Fenix ARB-L18-3400 battery is about 3 hours from depleted to fully charged with a 5 V/2 A charging adapter. Only Low output of white light mode and Low output of warm white light mode can be operated while charging.Once charging is completed, be sure to close the anti-dust cover.

*The headlamp can only be charged while using a Fenix ARB-L18 series battery.

*If the headlamp has been fully depleted, it will take about 4 seconds for the battery indicator(s) to function after charging begins.

Battery Level Indication
With the lamp switched off, single click either switch to check the battery status. Single click once again the indicator(s) will go out immediately, or without any operation the indicator(s) will last for 3 seconds. Each time the light is turned on, the indicator(s) will show the battery level and will last for 3 seconds.

• Four lights on: 100% - 80%
• Three lights on: 80% - 60%
• Two lights on: 60% - 40%
• One light on: 40% - 20%
• One light flashes: 20% - 1%

*Note: This only works with a Fenix ARB-L18 Series battery.

Battery Replacement
Unscrew the battery cover anticlockwise to insert the battery with the anode side (+) towards the inner side, then screw the battery cover back on. 

Intelligent Overheat Protection
The lamp will accumulate a lot of heat when used at high output levels for extended periods. When the lamp reaches a temperature of 60°C/140°F or above, it will automatically step down a few lumens to reduce the temperature. When the temperature drops below 60°C/140°F, the lamp will gradually recall the preset output level. 

Low Voltage Warning
When the voltage level drops below the preset level, the headlamp is programmed to downshift to a lower brightness level until Eco output is reached. When this happens in Eco output, one of the battery level indicators blinks to remind you to timely recharge or replace the battery till the battery runs out.

*Note: This only works with a Fenix ARB-L18 Series battery.

Headband Assembly
Notice: The headband is factory assembled by default.

Rotate the dial clockwise to tighten the headband, and rotate the dial counterclockwise to loosen the headband. When the headband hits its maximum length, keep loosening the headband and the operation direction will reverse. 

Usage and Maintenance

• Disassembling the sealed head can cause damage to the lamp and will void the warranty.
• Fenix recommends using an excellent quality battery.
• If the lamp will not be used for an extended period, remove the battery, or the lamp could be damaged by electrolyte leakage.
• Turn off and lock the lamp or take out the battery to prevent accidental activation during storage or transportation. 
• Long-term use can result in O-ring wear. To maintain a proper water seal, replace the ring with an approved spare.
• Periodic cleaning of the battery contacts improves the lamp's performance as dirty contacts may cause the lamp to flicker, shine intermittently or even fail to illuminate for the following reasons:
  A: The lamp is locked.
  Solution: Simultaneously press and hold the two switches for 3 seconds to unlock the lamp.
  B: Poor battery level.
  Solution: Recharge or replace the battery (Ensure battery is inserted according to the manufacturer’s   specifications).
  C: The threads, PCB board contact or other contacts are dirty. 
  Solution: Clean the contact points with a cotton swab soaked in rubbing alcohol.

If the above methods don't work, please contact the distributor.

Warning

• Do NOT place this headlamp in the reach of children!
• Do NOT shine the headlamp directly into the eyes of anyone!
• Do NOT place the headlamp near flammable objects, high temperatures can cause objects to overheat and become flammable/ignite!
• Do NOT use the headlamp in inappropriate ways such as holding the unit in your mouth, doing so could cause serious personal injury or death if the headlamp or internal battery fails!
• This headlamp will accumulate a significant amount of heat while operating, resulting in a high temperature of the headlamp shell. Pay close attention to avoid burns.
• Turn off and lock the lamp or take out the battery to prevent accidental activation during storage or transportation.
• The LEDs of this headlamp are not replaceable; so the whole headlamp will need to be replaced when any of the LED reach the end of its lifespan.