HPI Racing 100920 Pinion Gear, 21T (1M) 21 tooth Pinion Gear is an official HPI part machined from high strength steel to precise factory specs for a perfect fit and smooth gear mesh Designed for the Savage Flux HP truck, this line of pinion gears can also be used on applications that use 1M pitch and 5mm motor shafts Includes: pinion gear and set screw