The highly expandable "M4A1 MWS" with RAS (Rail Adapter System) mounted, corresponding to various optional parts, finally appeared in gas blowback! The dedicated blow back engine contains a cylinder of the largest series, 19 mm in diameter, and an unprecedentedly strong recoil shock occurs. Equipped with a new mechanism for improving durability including Z-system, the pursuit of realism of shape reproduction and texture, and ultimate gas blow back which combines the high accuracy of hit accuracy & performance like Tokyo Marui It is a model.