ProMag Industries Drum Magazine, 9MM, 50 Rounds, Fits SIG MPX, Polymer, Black DRM-A21 DRMA21

This drum magazine has housing constructed of proprietary DuPont Zytel based polymer. Additional components include an injection molded magazine follower and a spring formed from heat treated stainless steel. Fits SIG Sauer MPX 9mm;Heat treated stamped steel upper magazine housing ;Drum housing constructed of a proprietary DuPont Zytel based polymer;Injection molded magazine follower;Spring formed from heat treated chrome silicon wire