||I got this gear set as a replacement for the gear set in the KWA KM4-A1 2GX. Unfortunately, my original gear set wore down on the sector gear and piston, and since I was running an 11.1 Lipo at around 22-25 rounds per second, it was predictable that I would need to replace the gear set soon!
In comes this gear set! For the price, it is definitely a good investment, especially if you are aiming for that high rate of fire, but make sure you do use a low power spring (M120-M130 or equivalent max), because you could wear your gears down faster if you use a stronger spring.
This gear set was definitely worth it, the only reason I give it four stars though is because the floating gear set up did not work properly. I followed the steps to use the springs to help the gears float "perfectly" inside the gear box for maximum performance, but all they did was cause my box to lock up. Took them out and the box ran at 150% efficiency again!
Piston AND Speed Gear Set
Full metal teeth on piston
Floating Spring system didn't work (for me).
Overall, definitely worth it!
Rating: [4 of 5 Stars!]