Originally designed for the American market, the USP (Universal Self-loading Pistol) has found international acceptance as an accurate and ultra-reliable handgun. Features favored by U.S. law enforcement and military users provided much of the design criteria for the USP. The controls are uniquely American, influenced by such famous designs as the Government Model 1911 pistol. All USPs use a fiber-reinforced polymer frame stiffened by stainless steel inserts at areas subject to stress and friction. HK pioneered this use of polymer materials in the production of handguns more than 30 years ago with the development of the VP70Z and P9S pistols.