This is a standard 72 Tooth 48 Pitch Spur Gear for electric touring cars. This is the main gear of the vehicle that meshes with the pinion gear. Black nylon construction Multiple mounting holes for various applications One 72T Spur Gear Nothing. This is a direct replacement part. Total outer diameter: 39.2mm (1.55") Thickness: 5.3mm (0.21") cmc 05/11/02 ir/kh &