Full-capacity OEM magazines are the exact ones that Beretta ships with new Px4 pistols, so you know you have a replacement mag made to fit your gun. None of the compromises you make with cheap aftermarket mags. Heat-treated steel tube, "memory resistant" music wire spring that resists taking a set, self-lubricating polymer follower, and a removable polymer base pad for easy cleaning. Mfg: Beretta Usa SPECS:High-carbon, heat-treated steel, blued.