IMG Glock .45 ACP 13 Round Pistol Magazine Black. 45 ACP 13 Round Black Polymer Magazine for Glock 21. Mag body is made of virtually indestructible black nylon molded around steel inserts. Magazine spring is made from heat-treated chrome silicon wire for stiffness and durability. Witness holes are clearly visible to let the shooter know how much ammo is available at a glance. Designed for Glock Gen 3 and subsequent models. Manufacturers Lifetime Warranty. Specifications for IMG Glock .45 ACP 13 Round Pistol Magazine: Manufacturer: IMG Gun Make: Glock Gun Model: Glock 21 Caliber: .45 ACP Magazine Capacity: 13 Round Color: Black Quantity: 1 Fabric/Material: Polymer Package Contents: IMG Glock .45 ACP 13 Round Pistol Magazine What firearm models does the manufacturer say IMG Glock .45 ACP 13 Round Pistol Magazine is compatible with? The manufacturer says that IMG Glock .45 ACP 13 Round Pistol Magazine is compatible with Glock 21IMG GL-0010-13RD: Glock .45 ACP 13 Round Pistol Magazine Black