This magazine is for Rock Island's Rock Warrior pistol and is constructed of metal with a blued finish.The Rock Island Armory for RIA 3.10 Magazine is a standard factory replacement magazine. This magazine is for either RIA 3.10 models chambered in .45ACP and holds 10 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.