This side folding 6 position stock set up is perfect for storing or transporting your custom gun. It offers easy mounting on any MPA .45 acp gun. We install the rear stock on the upgraded folding adapter and the stock adapter. All you do is mount it up to the rear of your gun, thread in the button head bolt (provided) and secure it with the Allen wrench that we provide. *This part number for the Adapter, upgraded folding adapter, and 6 position AR stock. Upgraded folding adapter offers upgraded machined parts, machined improved locking buffer tube slot to prevent turning, upgraded hinge spring, improved, wiggle free locking hinge, slimmer design and harder coating. NFA rules apply.**TELL US IN THE COMMENTS SECTION OF YOUR ORDER IF YOU HAVE AN OPEN BOLT MAC-10, WE NEED TO GIVE YOU A DIFFERENT BOLT AND INNER THREADED BLOCK.