SpecialFire&reg; CREE XM-L2 U2 T6 Flashlight LED Bulb 5-Mode 1000 Lumens 3.7-4.2V for Ultrafire 501B 502B Surefire Surefire 6P 9P Comes with a lifetime warranty if purchase through ArizonaTacticalGear Runs on 2 x cr123 or 1 x 18650 rechargable battery. 3-6v working range Save batteries with 2-3 times the run-time over normal incandescent 5 Modes of Operation (High, Med, Low, Strobe, SOS) controlled with soft click of tail switch Smooth reflector for extreme ilumination distance and tightly focused beam