Made to Fit any 57 Series Pistol. MPA57SST Series. Includes Side Cocking Upper Receiver with Picatinny Rail, Hand Guard, with 4 Picatinny Rails, 16″ Barrel, Muzzle Brake, and wire stock kit including Stock, Adaptor and L Bracket with Jam Nut. This system will fit your MPA57 series pistol perfectly. Just remove your current upper, pull out the bolt and put into the new upper and install on your lower receiver. Takes 2 minutes. Also, the Adaptor has a 1 3/16-16 Thread in case you want to install an AR type buttstock instead of the Wire Stock. Call with any questions.