Jin Ming Upgraded Gearbox

Need a bit more power for your JM Gen9. Then this upgraded Jm9 gearbox is for you.
All the hard work done: shimming, greasing, and wiring.
What’s been upgraded:
– Metal 18:1 Steel Gears (Perfectly Shimmed)
– SHS Polymer Plunger with 14T Steel Teeth
– Alloy Fighting Bro Piston Head
– Green Over Sized O-Ring
– Strong Stainless Return Spring
– Metal Bearing Spring Guide
– 1.3 Tension Spring