Shield Arms S15 +5 Magazine Extension, Anodized Finish, Red, with Power Spring SA-S15-ME-5-RED The Shield Arms S15 Magazine Extension adds 5 rounds to your S15 magazine. Their 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.