The Umarex TAC Converter converts your CO2 Pistol into a tactical carbine. The TAC Converter is compatible with HK USP CO2 Pistols (BB gun and airsoft), S&W MP40 BB Gun, Umarex XBG BB Gun, Combat Zone Enforce CO2 Airsoft Pistol, and Walther P99 DAO Co2 Airsoft Pistol (model #s 2262020/2262030/2276008). This item adds stability by adding a folding stock and tactical foregrip to your pistol. It also has a lot of rail space for adding tactical accessories such as lasers, flashlights, and red dot sights. This is really the ultimate accessory to take your pistol to the next level.