The SM-9 is a machine pistol of Guatemalan origin and manufactured by Cellini-Dunn. It is blowback operated, firing from an open bolt and fed from 36 rounds magazine inserted in the grip. The layout of the receiver is somewhat simpler to that of a Sten with its internal components light in weight enabling a very high rate of fire. Its forward pistol grip can hold a spare magazine as well as handling the weapon when firing.