Airsoft kit ASKU CYMA: 1) Two options of handguard (155mm and 215mm) 2) Gas tube 3) Two options grips 4) Picatinny rail 5) DTK Kochevnik For installation, you need bolts and cakes m3 and m4. There is a video instruction for installation. Adjust the scale before installing the silencer, first print the threads (PLA scale 98%)