JG M4 / M16 V2 Gearbox

Jing Gong M4 / M16 V2 Gear box Replacement complete version 2 gearbox for M4 series AEG. It fits into most brands as a drop in replacement, but may not fit some. The FPS as standard are quite high (400fps) we recommend getting a lower power spring to change out before installing it into your gun.