Switches
The tail switch is the tactical switch, and the side switch is the functional switch.

ON/OFF
Tap
Slightly tap the tactical switch to momentarily turn on the light, release it the light will go out.
Fully press
Fully press the tactical switch to constantly turn on the light, press once again to turn off the light.

Output Selection
With the light switched on, single click the functional switch to cycle through Eco→Low→Med→High→Turbo.

Strobe
With the light switched on, press and hold the functional switch for 0.5 seconds to enter strobe, click once again to return back to General mode.

Boot-up Battery Level Indication
Each time the light is turned on, the battery level indicator will automatically display the battery status for 3 seconds.
Green constant on: saturated
Green flashes: sufficient
Red constant on: poor
Red flashes: critical
Note: This only works on rechargeable LI-ion 18650 battery.