Fenix PD35 850 Lumen LED Flashlight Cree XM-L 2 (U2) LED with a lifespan of 50,000 hours 5 Brightness Levels Plus Strobe Low-voltage warning function to remind you to replace the battery Reverse polarity protection guards against improper battery installation Uses one 18650 rechargeable Li-ion battery or two 3V CR123A Lithium batteries