The pouch is designed for 1 piece M4 (ar15, l85, and others with this type of magazine). The pouch has a self-locking locking mechanism, which means that the pouch is tight enough so that content does not fall out of the pouch but can simply been inserted or removed. This self-locking system allows for very quick magazine replacement. On the back side, the pouch is fitted with a molle binding for attaching to the vest or other equipment equipped with this binding. To extend the lifetime of the rubber we recommend always to remove the magazine from the pouch and leave them empty when storing the equipment.