The Nightstick TWM-852XL Xtreme Lumens Tactical Weapon-Mounted Single Switch Long Gun Light uses a CREE LED rated 850 lumens. Working in conjunction with a high-efficiency deep parabolic reflector it creates a usable beam of light rated at 245 meters. This weapon light attaches to a Picatinny Rail of a long gun to operate the momentary-on and constant-on lighting modes. The housing is constructed from aircraft-grade 6061-T6 aluminum. Includes 1 set of 1913 cross-rail inserts, 4 cross-rail mounting cap head screws, Allen wrench, and 2 CR-123 batteries.WARNING – This product can expose you to less than 0.01% of DEHP, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to http://www.p65warnings.ca.gov/.