These are Replacement Gears and Shafts for the Traxxas EZ-Start System. FEATURES: Steel main gear Nylon and nylon/metal gears Metal gear shafts INCLUDES: One 29T Steel Main Gear One 18T x 10T Nylon/Metal Gear One 37T x 11T Nylon Gear Two 3 x 14mm Metal Shafts One 3 x 5mm Brass Bushing REQUIRES: Traxxas vehicle with EZ-Start system. COMMENTS: Most GP models made by Traxxas have the EZ-Start system. sml 9/29/00 ir/jl