Weighing 2.3 oz. with a shockproof compact design, the Sightmark ReadyFire LW-R5 Red Laser Pistol Sight easily and securely attaches to your full-size pistol to take the guesswork out of aiming. Weaver/Picatinny-style mount attaches between the trigger guard and muzzle of any railed handgun. Visibility extends out to 20 yd. during the day and out to 300 yd. at night. Powered by two AG13 batteries (included) for up to seven hours. Operating temperature of -18°C to 49°C.