ProMag magazines are made in the USA and backed by a lifetime guarantee against manufacturers defects. Magazine springs are precision wound using heat-treated chrome silicon wire and each and every step of the assembly process is checked and double checked in order to maintain the same consistent level of quality.Features :50-Round Drum MagazineFits Ruger Max-9 9MM PistolMagazine Body Constructed of a Proprietary Dupont Zytel Based PolymerBlue Steel Upper Magazine TowerInjection Molded Magazine FollowerMagazine Spring Formed From Heat Treated Stainless SteelMade in the U.S.A.