Models K31 Stripper clip 8 20 1 ARC helmet rail to Picatinny mount 10 130 0 KP-9 13 131 0 FGC-9 mk2 (FOR RESEARCH PURPOSES ONLY) 27 352 3 3D printable 5.56x45 AR-15 style magazine 14 198 0 Improved ECM Barrel Fittings 28 286 0