The Shield Arms Glock 17/22/34/35/19X/45 Magazine Extension adds 5 rounds to your Glock 17/19X/34/45 magazine, and 4 rounds to your Glock 22/35 magazine. Their unique, easy access floor plate design allows you to easily 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.