The STEN was a British submachine gun used during World War II. It was a simple and inexpensive weapon that was mass-produced and widely used by British and Commonwealth forces. The STEN was a blowback-operated, magazine-fed submachine gun that fired from an open bolt. It was designed to be easy to manufacture and maintain, and could be produced quickly and cheaply. The STEN was reliable and accurate, and was used in a variety of roles, including close-quarters combat and as a support weapon.