Rock Island 6503 1911 8rd 9mm Luger Blued Metal
https://www.tandktactical.com/shop/812285021171-rock-island-6503-1911-8rd-9mm-luger-blued-metal-5146
https://www.tandktactical.com/web/image/product.template/5146/image_1920?unique=835f3c1
This replacement or spare magazine is compatible with your Rock Island 1911.
