The POF4 is an impressive mean looking semi-auto (irreversible) pistol, chambered in 9×19 mm Para caliber produced by Pakistan Ordnance Factories Ltd (POF). It is based on the Heckler and Koch design and employs delayed blowback, roller locked system. Similar products in POF inventory are the POF5 which is just like the select fire 9×19 MP5 being produced by them for the military, minus the stock. The POF5 as well as POF4 have been classified as pistols because they have a reduced magazine capacity of 15 rounds as against 30, have semi-auto only firing capability (irreversible) and lack a butt stock; thus reducing the weapon’s length also. The similar variants being produced by the POF for military are the SMG PK/PK1 and the SMG MP5A2/MP5P3.