It's simple but it works to save your expensive brass the easy way! This zippered nylon brass catcher pouch works for the Mac-10, M-11, AK-47, and AR weapons. Fits most side cocking uppers and standard top cockers on all Macs, SMG, Semi Auto and Master Piece Arms A guns. Mounts to the weapon with a velcro strap and has an inner metal frame the surrounds the side of the upper to collect the brass. Inner frame can be bent or modified to fit specific components. (Gun and other components sold separately)