OEM replacement magazine for the T4E Smith & Wesson M&P9 .43 caliber paint ball pistol. This drop free magazine house 8 shots and a single 12 gram CO2 cartridge and also features a quick pierce CO2 valve. To pressurize the magazine, strike the button on the bottom with an open palm and the CO2 cartridge will pierce and be ready for use. This design saves wear and tear on the valve by pressurizing the magazine only when needed.