Bore cartridge fits .223 REM/5.56 NATO firearms such as the AR-15,M4,or the M16. High quality brass constructed material Cartridge projects laser through the barrel for fast zeroing on target. Safer than traditional stock muzzle devices for your airsoft. Shines a maximum output of 5mw for a great distance. In the Box 1X Laser Cartridge Bore Sighter Specifications: Manufacturer NcStar Build Brass Weight 0.3oz Length 1.8 Inches Maximum Output