The BlackHawk CQC Matte Finish Mag Pouch - Single Stack is a magazine pouch with a built-in tension spring. This tension spring will hold your magazine in place until you need it and will allow the use of a variety of magazines in each pouch. The BlackHawk CQC Matte Finish Mag Pouch - Single Stack has a proprietary belt clip that functions as a clip-on design but has the stability of a belt loop. The stability of the CQC Matte Finish Mag Pouch - Single Stack by Black Hawk is due to the hold and strength these mag cases get from the aggressive talon and special Carbon-Fiber material. The single stack magazine pouch works with all caliber single column mags, from 9mm to .45 caliber.