... HA Type III *Waterproof: IPX8 (Underwater 100 meters) *Switch: Head Twisty Switch (Magnet control Switch) *Modes: Max-Mid-Min-Strobe-SOS *Battery: 1PC ... battery correctly inserted, screw the tail cap onto the body fully. Rotary Head Twisty Switch to change modes between Max,Mid, ... Min,Strobe,SOS.*Remove the tail cap, insert the batteries ...