This is the replacement 20 Tooth Drive Gear for the Axial AX10 Scorpion Rock Crawler. Steel construction, gunmetal in color Replaces a worn or damaged Drive Gear (top gear) One 20 Tooth Drive Gear (top gear) Installation following the model manual Width: .39" (10mm) Inside Diameter: 5mm Outside Diameter: .45" (11.5mm) Number Of Teeth: 20 For the shaft that this gear rides on order AXIC3197 kpm11/20/2007 ir/jxs &