G&P Stainless Steel Gas Exit Valve Assist with O-Ring for Marui MWS M4A1 GBB

G&P Stainless Steel Gas Exit Valve Assist with O-Ring for Marui MWS M4A1 GBB Stainless Steel Construction Suitable for Tokyo Marui M4A1 MWS GBB Rifle Magazine Included MWS Magazine Valve O-Ring