The TWM-852XL Tactical Weapon-Mounted Long Gun Light uses a CREE LED rated 850 lumens for 2.5 hours providing a beam distance of 245 meters. The rear facing single switch provides both momentary and constant-on lighting operation. Designed to securely attach to a long gun picatinny rail, the IP-X7 rated waterproof housing is constructed from aircraft-grade 6061-T6 aluminum. The TWM-852XL comes preinstalled with one set (2) cross-rail inserts. Comes with an Allen wrench and 2 CR123 lithium-metal batteries.