Does the fighting bro v3 gearbox fit in m4a1 j9

im looking to upgrade my j9 and that looks pretty good on monkee mods for the price does it fit

It’s not a v3 , it’s a model 3.0 and is a v2 split box.
Probably not going to fit gen9

bugger thanks i’ll look for more

It can fit if you hack the back out of receiver just above the handgrip. Its fuggly though.