This is the optional Robonson Racing 18 Tooth Pinion Gear for the Team Associated RC18T RTR racing truck (ASCC2011). FEATURES: Aluminum construction, silver in color INCLUDES: One 48 pitch pinion gear One 3x3mm set screw REQUIRES: Installation onto the motor shaft SPECS: Length: .39" (10mm) Mounting hole diameter: 2mm KJW 5/15/05 ir/jxs