This is the Steel Clutch Bell/Spur Gear Combo set for the HPI Savage truck. FEATURES: Steel construction Natural steel color YOU WILL RECEIVE: One spur gear One clutch bell Two small Robinson Racing Products decals REQUIREMENTS: Removal of stock parts for assembly SPECIFICATIONS: Teeth count on spur gear: 52 teeth Spur gear outer diameter: 53.3mm (2.10") Spur gear inner diameter: 8.0mm (.315") Spur gear thickness at teeth: 6.6mm (.261") Teeth count on Clutch bell: 14 teeth Clutch bell bearing journal diameter: 10mm (.394") Clutch bell outer diameter: 28mm (1.10") Clutch bell inner diameter: 7.9mm (.311") COMMENTS: Instructions