The USP is a popular HK pistol. Umarex USA offers a couple of version in their airsoft line. One being the single action spring operated USP and the other being a fast action, powerful HK USP that's power driven with a single 12 gram CO2 capsule. UMAREX holds the worldwide exclusive HK-trademark and exterior design copy license for use with this UMAREX product, granted by HK, Inc., U.S.A. Licensed Trademark of Heckler & Koch GmbH