RetroArms CNC Aluminum 7075 Gearbox (8mm) for Tokyo Marui SOPMOD M4

The Retroarms CNC Gearbox for Tokyo Marui SOPMOD M4 allows the weapon to operate smoothly and reliably under high internal stress. This gearbox shell is designed to use upgraded Cylinder, piston, piston head and spring guide, and even GATE Titan compatible. Crafted from CNC Aluminium this is a highly durable upgrade part which will last a long time! With such a strong gearbox you have more options for internal upgrades without worrying about parts being brittle and weak. It perfectly sits into the reciever and all fire modes safe - semi - auto are working without problem, feeding on semi and full auto works also perfectly. Gearbox has 8mm slots for bushings/bearings.