Sig's MPX redefines the submachine gun category with a new level of operator safety, in-field adaptability and proven reliability in the harshest environments. The MPX K AR pistol has an unconventional design, unmatched performance, and familiar AR handling. It is completely ambidextrous, a with dual-sided selector switch, magazine release, charging handle and bolt release. The SIG MPX operates from a fully-closed and locked rotating bolt and a short-stroke gas piston. A full-length picatinny rail allows for solid, consistent mounting of optics and targeting lasers. This model has a 4.5" threaded barrel, hard coat anodized black metal finish, pistol stabilizing brace and a short aluminum KeyMod handguard with handstop.