This is the replacement 66 Tooth Spur Gear for the HPI E-Savage Series. Composite nylon construction, black in color Replaces a worn or damaged spur gear One 66 tooth Spur Gear Installation following the model manual Outside diameter: 2.13" (54mm) Thickness: .31" (8mm) For the Slipper Clutch parts order HPIC8332 kpm12/05/2006 ir/jxs &