The Tracker Safe PDM is a must have safe accessory. It can hold 1 pistol magazine and 1 AR style magazine. It can be placed anywhere there is carpet; i.e. back of safe doors, inside walls of safes, cars, trucks, etc. Keep your pistol magazines ready and organized with the Tracker Safe PDM. The PDM pocket is constructed of strong durable nylon fabric on the front and the back is fully covered in Velcro. In the center is a thick plastic core that gives the PDM its rigidity. Both the larger AR magazine holder and the small pistol magazine holder are made with nylon fronts and thick elastic sides that hold the magazines firmly in place. The elastic stretches to fit most magazines on the market. Please test your safe's carpet for compatibility with Velcro.