The STEN (or Sten gun) was a British 9 mm submachine guns used extensively by British and Commonwealth forces throughout World War II and the Korean War. They were notable for having a simple design and very low production cost. STEN is an acronym, from the names of the weapon's chief designers, Major Reginald V. Shepherd and Harold Turpin, and EN for Enfield. The Sten was a blowback-operated submachine gun firing from an open bolt with a fixed firing pin on the face of the bolt. Denix has done a fantastic job in replicating the working bolt action.