The fusion engine was installed by Rudy at Bingo Airsoft. External parts include a clone zenitco pistol grip, matrix wood kit, The original pkm furniture, a bakelite pistol grip,two pkm mags and a spiked flash hider. The internal parts include a m249 style fusion engine, 500mm orga wide bore, Bullgear hopup, Prometheus purple bucking, low-flow gold poppet and a red nozzle. Also included is a custom high-speed magazine made by Rudy. which holds over 5000 rounds and can feed at 30 rounds per second. The pkm comes with an amped duel tank rig and 2 ninja 90 cu tanks. $700 shipped.