Heckler and Koch 81000343: The HK USP (Universal Self-loading Pistol) is the first HK pistol designed especially for American shooters. Features favored by the U.S. military, law enforcement agencies, and civilian users provided the USP\'s design criteria. Its controls are uniquely American, influenced by such famous designs as the Government Model 1911 pistol. The USP Series\'s polymer frame was designed using HK engineers\' technical experience to develop the world's first composite material pistols, the HK VP70Z and P9S. Major metal components like the one-piece, machined steel slide are corrosion-resistant and treated with a special "HE" (Hostile Environment) protective finish. The HE finish is a tough, nitro-gas carburized black oxide coating, and resists even the worst types of corrosion and wear, including exposure to saltwater. To reduce barrel wear, most USP Pistols have polygonal cold hammer-forged barrels. This feature not only ensures longer barrel life and easier bore cleaning but produces a better gas seal behind the bullet for increased muzzle velocity.