This is the Optional 32P 68T Spur Gear for the Traxxas T-Maxx Truck. This mounts to the spur gear shaft and is driven by the clutch bell. FEATURES: Strong nylon construction Black in color INCLUDES: One 68T spur gear (main gear) REQUIRES: Assembly onto the kit. SPECS: Tooth: 68 Pitch: 32 Thickness: 5.6mm COMMENTS: This is a direct fit hop-up. Reference the T-Maxx manual for different ratio combinations. Using a smaller tooth spur gear will give you higher speeds, and using a larger tooth spur gear will give you more torque. jim 1/18/2001 ir/jl