Alien Gear Holsters Single Mag Carrier, Black, Fits 9MM/40 Caliber Double Stack CMCS-4-D The Cloak Mag Carrier is the most innovative magazine holster on the planet! Built with a premium engineered polymer" Alien Gear Holsters' newest addition is capable of being worn as an IWB mag carrier (inside-the-waistband) or OWB Mag Carrier (outside-the-waistband). The comfortable" concealable mag carrier is also capable of cant and retention adjustment - everything you could possibly need in a magazine holder!