This is a genuine factory GLOCK 21 magazine for the .45 ACP cartridge and is designed to work in all previous versions of the GLOCK 21 including the Gen4.

It features the double cut magazine body and will work if you have reversed your magazine release on your Gen4 GLOCK 21. These magazines drop free from the gun when the release button is pushed, allowing for a quick and smooth reload with your next magazine. Each magazine is constructed from black polymer and has a metal spring.

Features and Specifications:
Material: Polymer and Steel
Capacity: 13 Rounds
Caliber: .45 ACP
Color: Black
GLOCK Genuine Factory Part
Metal Spring
Flat Base-Plate
Double-Cut Body

Fits:
GLOCK 21, 21SF, 30, 30S, 30SF, 41