ProMag Industries Magazine, 9MM, 28 Rounds, For Glock 43X/48, Steel Construction, Blued Finish, Black GLK-A23 ProMag magazines are made in the USA and backed by a lifetime guarantee against manufacturer's 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.