Compatible with most .45 ACP 1911 magazines, the Wilson Combat® 1911 .45 ACP 8-Round Spring & Follower Kit is an easy-to-install, drop-in upgrade kit, designed to deliver superior reliability and smooth feeding performance at an affordable price. Engineered to deliver exceptional reliability right out of the box, this kit includes a high-tensile steel spring and heat-treated polymer follower for lasting durability, lightning-fast feeding performance, and smooth, jam-free operation.