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.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.Caliber: 9mm LugerCapacity: 5rdFinish: AnodizedModel: Magazine ExtensionMaterial: AluminumCapacity: 5