Semi-auto steel BB airgun pistol. Green fiber-optic front sight and fixed rear sight. Full blowback action for realistic feel; 16-round drop-free magazine (spare magazine part number: 2251510). Shoots .177 caliber steel BBs at up to 410 FPS. Powered by a 12-gram CO2 capsule (CO2 NOT included. To ensure a proper seal and for best performance, Umarex-brand CO2 is recommended.).