This is a Pinion Gear with a 3.8:1 Gear Ratio for the S280 Gearbox. For use with the Great Planes Park Flyers. FEATURES: Replace worn pinion gear or change your gear ratio INCLUDES: One brass 12 tooth pinion gear One mini tube of Thread Locker to secure pinion to motor shaft REQUIRES: One T-280 motor Installing pinion gear onto motor shaft SPECS: Outer Diameter: 6mm Hole Diameter: 2mm COMMENTS: The higher number of teeth on a pinion gear results in higher speed of your model. The fewer number of teeth gives more torque. For T-280 motor, use GPMG0300. JXS 12/01/00 ir/jl