This magazine is for Rock Island's 1911 pistol and is constructed of metal with a blued finish.The Rock Island Armory 1911 Full Size Magazine is a standard factory replacement magazine. This magazine is for High-Cap A-2 1911 models chambered in .45ACP and holds 13 rounds of ammunition. It is made of steel and is made to Armscor/Rock Island Armory specifications and tolerances, using the same manufacturing and materials as the original equipment magazines, ensuring perfect fit and operation. Features: Polymer base plate