Tactical CREE IR NVG Infrared LED Spare Bulb for Ultrafire Surefire, Hugsby Flashlight Torch Etc. Powered by: CR123A 3.6 x 2 or 18650 3.7v x 1 Operating voltage: 3.7V - 9V Durable aluminum reflector---Smooth ---Mirror like Size(mm): 26.5(Diameter) Peak Wave Length : 850nm