The tyrant cnc magazine extension are designed to increase the ammunition capacity of springfield armory echelon's 15 and 17-round magazines by an additional 5 rounds of 9mm.Each springfield armory echelon magazine extension is cnc machined from t6061 aerospace-grade aluminum.The finishing process involves bead blasting followed by a hardcoat anodize.Caliber: 9mmCapacity: 5rdMaterial: AluminumCapacity: 5