Shield Arms Glock 17/22/34/35/19X/45 +5/4 Magazine Extension - Black - The Shield Arms Glock 17/19X/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. Shield Arm's 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.