The Sten is a sub machine gun of UK origin. It was developed during the early stages of World War 2 in order to supply British forces with an effective sub machine gun at low cost. The simple design proved to be highly effective and for its role in World War 2 it has become an iconic firearm. Due to its simple design it has been produced in makeshift factories and it was used by various resistance and partisan forces.

The Sten is a blowback operated weapon that fires from the open bolt position. The design is very simple with a tubular receiver, side inserted magazine that doubles as a grip and metal tubular grip and stock. The Mk I and V had a wooden furniture and were of reasonable production quality. The Mk II and III that made up the majority of the production were much cheaper and of limited quality, however still effective and reliable.

The Sten fires the 9x19mm round from 32 round magazines. It fires only fully automatic at a rate of fire of about 550 rpm. Due to the open bolt design the maximum range is about 100 meters. The silenced versions were usually fired in short burst or semi-automatically due to their tendency to heat up.

The Sten was widely used by British and Commonwealth forces during World War 2. It was supplied to various allied and resistance forces. After the war it was briefly used by various European nations but it was quickly replaced in Western service by more modern sub machine guns. Many were scrapped or ended up third world nations.