The ProTac series expands into weapon-mounted lights with this light featuring a dedicated fixed-mount for Picatinny rails. It uses either a remote switch with momentary/constant on operation or a standard push-button tail switch, and can run on either a lithium battery or an easy-to-find alkaline battery. ProTac Rail Mount 1 Specs: Dual fuel – uses one AA alkaline or CR123A lithium battery (both included); also accepts AA lithium CR123A lithium battery output: High: 350 lumens; 12,000 candela; 219m beam; runs 1.75 hours Low 40 lumens; 1,380 candela; 19m beam; runs 14.5 hours AA alkaline/AA lithium battery output: High: 150 lumens; 4,950 candela; Mfg: Streamlight