The StreamLight ProTac® Rail Mount 2 is a fixed-mount, dual fuel long gun light with a maximum light output of 625 lumens and a range of 625 meters. It is machined from durable anodized aluminum with an impact-resistant tempered glass lens. The impact resistant Borofloat® glass lens is high temperature, shock mounted and AR coated. The light source offers C4® LED technology and is impervious to shock with a 50,000 hour lifetime. Its engineered optic produces a concentrated beam with optimum peripheral illumination. It is supplied with 2 CR123A Lithium Batteries.