HPI Racing 41 tooth Nitro spur gear is constructed of black nylon one-way bearing type spur gear. This will only work with a one-way bearing, will not work properly with 1st gear adapter. The included gear ratio chart list recommends gears for specific HPI vehicles. This product includes one 41 tooth Nitro spur gear. One gear ratio chart and installation guide.
HPI Nitro Two-speed transmission or one-way bearing