SpecialFire&reg; CREE XM-L2 U2 Flashlight LED Bulb 3 Mode 1000 Lumens 3.7V-4.2V for Ultrafire 501B 502B Surefire Surefire 6P 9P Comes with a lifetime warranty if purchase through ArizonaTacticalGear Voltage Range 3.7-8v. Increase brightness up to 1200 lumens with the US made CREE XML-U2 3 Mode LED Never buy bulbs again LED lifetime over 100,000 hours / Save batteries, 3 times the run-time!!! 3 Modes of Operation (High, Low, Strobe) controlled with soft click of tail switch Smooth reflector for extreme ilumination distance and tightly focused beam