This is the Castle Creations 32P 26T Pinion Gear for Monster Trucks. FEATURES: Aluminum construction INCLUDES: One 32P 26T Pinion Gear One 4x4mm Set Screw REQUIRES: Installation on the motor shaft SPECS: Outer Diameter: 22.3mm (0.88") Hole Diameter: 5mm (0.20") Length: 11.9mm (0.47") Castle CreationsPart CSE010-0065-05