CYMA Sport Complete Ver II Gearbox w/ Quick Change Spring for M4 Series Airsoft AEG (Type: Front Wired / High Speed Motor)

"i only ever buy these gearboxes for the shell and the quick change capability, because it's some of the best i've seen.
the gearbox itself needs a LOT of work to run reliably. the mosfet is trash, the motor is trash, the shimming is trash, the grease is trash, and the lack of aoe correction on the full polymer piston is trash. oh yeah, and the piston itself is trash, and the piston head has a stupid screw that's unlike any other i've seen. i do like the cylinder though.

complaints aside, this shell is not only great for budget builds but it also has one of the best quick change spring systems i've ever seen. this gearbox is great if you're willing to strip it down and rebuild it, but it's pretty expensive if you're just gonna keep the shell like i do. no where else you can get it though, other than a boneyard gun

"This gearbox with a RHop barrel is unbelievably nasty! 10 out of 10 I switched my stock gearbox with this one and used a 6.02 tight bore barrel and went up on BB weight between.30-.36 and it’s sending it every time definitely would recommend to buy!

"very nice GB, it actually come with a full cylinder, rear wiring with deans, plenty of length. I slapped it in my cyma M16a1 as it was the previous gen without these internals, I had to shave down the full stock mounting screw by about 1/8" for proper fit. other than that its shooting 1.4J consistently, 330 fps with .28s and about 20rps on the motor. Ill be buying a second one of these.

"best gearbox for the price

internals. nicely shimmed 18:1 gear
m120 spring
quick spring change system that doesn't protrude out the back end of the gearbox like other brands
metal ball bearing spring guild
electronic trigger
motor has some nice torque far more than any high end gun which is a huge plus
redesigned for easy teching and is reinforced far better than any other gearbox
plastic piston head with 1 metal tooth piston...generic stock cheap part
plastic nozzle
ported cylinder
semi proprietary tappet plate...its just has the front sides shaved down to accommodate the thick reinforcement


recommend
replacing oring on the piston and nozzle with a internal o ring nozzle since there is little to no compression which is know to be a problem with cyma guns
wiring needs to be replaced

definitely recommend fr 55$ u are getting this thing for a steal , the trigger alone is worth the price

"I ordered three of these gearboxes and each one was the same quality wise. One ETU burnt up when I fired it three times. No inline fuse to stop the fragile unit from smoking on a low powered 7.4. Compression is next to nothing. Got 345fps on 0.2g bbs. Motors are very low end, full auto is very slow. Overall, 2.5/5. Id rather spend the extra money and get the full Lonex gearbox and my own motor next time.