This is the A1 style receiver. The upper was originally a preban that the flash hider was sleeved and the bayo lug was neutered. It is the carbine with the long flash hider to make it 16". The upper comes with 20 sten mags with haversack, old style oly paddle mag block, and 150 rounds of Winchester white box 115grain ammo. 10 of the mags are converted 10 are not. By converted I mean with the old style oly block the mags need a shot set screw placed in the back of the mag near the top to lock in. Looks very simple to do. Pics will be available upon request. Price is $450 obo shipping included for the package. All reasonable offers will be considered.