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 :DuPont Zytel Polymer ConstructionHeat treated Stainless Steel Internal SpringInjection Molded Polymer FollowerMagazine Body Constructed of Heat Treated Steel with Phosphate Finish30 Round Drum Magazine