This is an Optional Aluminum Reverse Primary Gear for the Traxxas T-Maxx. This gear is located in the gearbox, and replaces Traxxas part #4995. FEATURES: Machined aluminum Bronze color INCLUDES: One 22 Tooth Reverse Primary Gear One Pin REQUIRES: Assembly into a T-Maxx truck. SPECS: Length: 17.3mm (.698"") Teeth Outer Diameter: 24.1mm... more...