This Mec-Gar magazine has a carbon steel tube, heat-treated for strength and a higher tensile music wire spring with a steel follower and welded floorplate. This model is compatible with 1911 full-size government pistols. It has a 7-round 45 ACP capacity and a blued finish. Features: Full-size government Carbon steel tube, heat-treated for strength Higher tensile music wire spring Steel follower Welded butt-plate