The TWM-852XL Xtreme Lumens Tactical Weapon-Mounted Long Gun Light uses a CREE LED rated 850 lumens for 1.75 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. an Allen wrench. and two CR123 lithium-metal batteries.