P.O.F. stands for PAKISTANI ORDNANCE FACTORY. The SMG5-K is a slightly-different-from-the-original pakistani copy of the german HECKLER&KOCH MP5-K compact submachinegun. It fires the same .9x19mm-Parabellum than the original, has a S-E-F trigger group, but it can ONLY mount proprietary reduced-capacity mags (20 or 25 rounds instead of 30 or 35). It has no stock; instead, it is equipped with a sling ring.
Photo and information from: PIERANGELO TENDAS