This is the HPI Savage 47T Spur Gear. This replacement 47T spur gear is intended for the HPI Savage monster trucks platforms that are equipped with the high speed gear and a 25+ size engine. The smaller diameter of the 47 Tooth gear delivers higher top speed and also makes room for the installation of a larger clutch bell without the need to modify the truck. Package includes one 47T spur gear and one gasket.