This is the optional 22 Tooth 48 Pitch Pinion Gear for the HPI Switch On-Road Car. FEATURES: Constructed of steel INCLUDES: 22 Tooth 48 Pitch Pinion Gear REQUIRES: Installing on motor shaft and tightening set screw SPECS: Diameter of Hole: 1/8" (3mm) Number of Teeth: 22 Pitch: 48 jxs 12/12/11 ir/jxs