Maple Leaf AR Bolt Action Upper Receiver Conversion Kit for GHK M4 V2/ V3 GBB Airsoft Rifle

Key Feature Metal Construction Airsoft Upper Receiver Design For Convert Your Gas Blow Back Rifle to Bolt Action Rifle 20mm Picatinny Rail on Top Come With The Bolt & Adjustable NPAS Loading Nozzle Adjustable Dart Flow Design (use M1.5mm hexagonal rod to adjust) Suitable For GHK M4 V2/ V3 Gas Blow Back GBB Airsoft Rifle