ATF approved! Adapter with Shockwave Blade Pistol Stabilizer for Master Piece Arms 9mm. 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 Adapter, pistol buffer tube and Shockwave Blade, other parts sold separately. weighs about 12 ounces.**DOES NOT FIT NEWER 9MM MODELS without the threaded hole on the underside at the rear.