Shield Arms +5/4 Magazine Extension, Aluminum, Anodized Finish, Mud, Fits Glock 19/23 G19-ME-5-MUD The Shield Arms Glock 19/23 Magazine Extension adds 5 rounds to your Glock 19 magazine" and 4 rounds to your Glock 23 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.