If you are looking for a tactical upper system with quad rail, a 10 inch rifled barrel, a thread adapter, TITAN muzzle brake, vertical tactical grip, and a side cocking upper with a rail for your choice of optics, then this is for you! It improves the accuracy and performance and offers the rails to mount your choice of fore grip, laser, tactical light or anything else. Just slide in your bolt assembly, drop into your receiver, lock into place and its ready to go. Works with all MPA .45 acp guns, Mac-10 Semi and SMG models. (gun & other components sold separately)* Addition of this item may require additional paperwork to be filed with the ATF, check with your local dealers.**LIMITED AVAILABILITY-PLEASE CALL BEFORE ORDERING***