FIRST Japan feature an FD-Type M17 PDW Kit that they sell at their stores. Based on the Flux Defense MP17 Chassis PDW Conversion Kit, this is compatible with the SIG Air M17/P320 Gas Blowback Pistol. No idea yet if it can be used with the F17 GBB Pistol designed by WE Airsoft as well as the upcoming P320 GBB Pistol from Tokyo Marui.