Compatible with Wilson Combat® #500, #500B, #500C, and #500BC magazines (not included), the Wilson Combat 1911 ETM .45 ACP 8-Round Spring & Follower Kit is a drop-in upgrade kit, designed to improve the overall reliability of your stock 1911 magazine, delivering reliable feeding performance with simple, tool-free installation. This kit includes 1 high-tensile steel spring and 1 heat-treated polymer follower for exceptional, field-ready performance—right out of the box. Made in USA.