ATF approved! Adapter with Shock wave Blade Pistol Stabilizer for Master Piece Arms .45acp with our Folding Adapter. It bolts to your gun and maintains a tight precision fit under rapid fire with the aid of a machined set screw, that bolts into the existing rear threaded hole. *This part number for the Folding Adapter, pistol buffer tube and Shock wave Blade, all parts to bolt it to your pistol.**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.