The weapon was fed from a 32-round box magazine inserted in the side and had an unusual twist-action bakelite-covered handguard.
While this very crudity was a positive asset in the straitened circumstances the British found themselves in during the war, a more refined and durable variant was requested.
The Sten Mark V was developed to fill this need during 1944, adding a wooden stock, forward pistol grip and better construction.
The EMC used blowback action but cycled, faster than the Sterling and all of the earlier Sten variants, at 600 rounds per minute.
It came with unusual features, notably a Bakelite pump action foregrip, a hinged magazine insert which could be pivoted backwards to allow jams to be cleared without having to remove the magazine and to facilitate cleaning, and a safety switch in the pistol grip, easily operated by the users thumb.