Cree XR-E P4 Aluminum OP reflector Harden glass lens T6061 Aluminum Alloy, Type III HA 1 AA battery (1.0-1.5v) Head dia. 19.5mm, tail dia. 17mm, length 85mm Weight 32g (battery not included) Twisty type switch 10m water-resistance Multi-mode output: Med/Low/High/Strobe(10Hz)/SOS Output level: about 40/20/80 Lm Run time: about 7/30/2 hrs.