Police in the United States usually carry a handgun on duty. Many are required to be armed on-duty and often required to have a concealable off-duty handgun. Among the most common sidearms are models produced by Glock, Smith & Wesson, SIG Sauer, Beretta, and Heckler & Koch, usually in 9mm, .40 S&W, .357 SIG (US Secret Service & other Federal Law Enforcement agencies) or .45 ACP.