S15 +5 Extension - Shield ArmsThe Shield Arms S15 Magazine Extension adds 5 rounds to your S15 magazine. Our 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. Don't want to do the installation? Check out our S15 Pre Installed Mag Extensions here. Features Unique easy access floor plate design to