The GHK 40rd GMAG Gas Magazine has a Polymer external housing with metal internals containing a high-flow output valve. Since it was made specifically for the G5 / M4 Gas Blow Back Rifle series, it only stores 40 round 6mm BBs which is quite a lot for a GBB mag and a slot where you insert green gas.
Prowin '30rd EVO' 50rds Gas Magzines for Tokyo Marui M4 MWS / WA M4 GBBR Series
50 round capacity.
Improved gas efficiency.
Tokyo Marui MWS system GBBR.
Tokyo Marui Type 89 J.G.S.D.F GBBR.
Western Arms (WA) System M4 GBBR.
With an extremely prolific background, Prowin has been one of those names in the airsoft industry that is easily recognizable. Producing everything from their industry leading hop-up chambers to highly efficient gas magazines, when you see Prowin, you know you are in good hands.