CO2 powered BB guns are great fun for plinking and target shooting. This HK USP holds 22 rounds in a heavyweight magazine that also houses the CO2 cylinder that powers this BB pistol. It has an ambidextrous magazine release, integrated accessory rail and realistic hammer movement. This is a great practice pistol for 9mm USP owners. For just pennies, you can shoot for hours. Features: CO2 powered Ambidextrous magazine release Realistic hammer movement