The Shield Arms S15 +10 Magazine Extension adds 10-rounds to your S15 magazine. Shield Arms' unique, easy access floor plate design allows you to quickly access the spring and follower without having to remove the extension from the magazine body. Comes with a 100% lifetime warranty, and the Shield Arms Spring for Life guarantee. Features: Compatible with Shield Arms Gen 2&3 S15 magazines Index cuts on the extension body to increase grip when coming out of a magazine pouch. Machined from billet 6061 aluminum Type 2 anodized Comes with a 15 coil plus power spring Fits Shield Arms S15 magazine only Proudly made in the USA Lifetime warranty