The ProMag Ruger Max-9 9mm 20-Round Steel Extended Magazine delivers reliable performance for your favorite 9mm pistol at a price that's hard to beat. This aftermarket magazine is constructed with heat-treated steel and features a black oxide finish for superior strength and corrosion resistance, ensuring reliable field performance. The injection molded magazine follower and heat-treated chrome silicon wire spring ensure smooth, dependable feeding and proper cartridge alignment in any informal target shooting and self-defense situation. Includes precision-machined witness holes. Compatible with Max-9 handguns ONLY. 20-round capacity.