Patented double-stack design, for use exclusively with the Mossberg 590M Mag Fed Shotgun. Features hardened steel feed lips, over-molded shell ramps, easy grip molded design, proprietary self-lubricating polymer magazine body material, removable floor plate for easy cleaning, and a tough black oxide finish on the steel components. Also available in 10 and 15. For use with 2 3/4″ shells only.