This is a Novak 5mm Bore Steel Mod 1 Pinion 3-Pack. Novak hardened steel pinion gears are now available in three packs! This allows drivers to experiment with gear ratio changes, while at the same time saving money by giving drivers the option to purchase a pack of gears, instead of buying individually! These heavy-duty gears are a necessity when converting 1/8-scale nitro off-road vehicles for brushless electric use. The gear pitch fit's seamlessly with the Mod 1 spur gears commonly found on 1/8-scale Nitro vehicles and will work perfectly with Novak’s HV High-Voltage Brushless Motors, as well as any other brushless motor with a 5mm output shaft.