This is the Mod 1, 18T, 5mm Pinion Gear for use on the Ofna 1/8 Hyper 9e Buggy Kit (OFNC4351). FEATURES: Steel construction Black in color INCLUDES: One 18T 5mm Mod 1 Pinion Gear Two 4x4mm Set Screws REQUIRES: Installation on motor shaft SPECS: Length: 12mm (0.47") Inner Diameter: 5mm (0.20") Tooth: 18 OfnaPart OFN29329