This is an optional 65T Steel Spur Gear and Hi Performance Slipper Unit for the Traxxas E-Revo with Mamba system from Robinson Racing. FEATURES: Steel construction Silver in color YOU WILL RECEIVE: 65 tooth steel spur gear Aluminum back plate Hex slipper pad 7x13mm bearing Aluminum spacer Four cone washers Instructions Decals REQUIREMENTS: Installation onto E-Revo lmm 04.28.10ir/jxs &