Provide the option of being able to change your gear ratio for different track conditions Durable metal construction for long-lasting performance for Traxxas 1/10 4-Tec Bandit Chevrolet Drag Slash Fiesta Raptor Rustler Stampede Supra Motor Pinion Parts The pinion gear shaft diameter or bore is 3.175mm, make sure your RC motor shaft have the same diameter 48P is the pitch of each tooth on the pinion gear and the 19T 20T 21T 22T 23T is the number of teeth on the pinion gear. You have to make sure your spur gear and pinion gear have the same pitch, or the teeth won't mesh Comes with set screws for each pinion gear, the pinion gear combo set also included a screwdriver, easy to install

Package include:

1 X 48P 3.175mm 19T pinion gear

1 X 48P 3.175mm 20T pinion gear

1 X 48P 3.175mm 21T pinion gear

1 X 48P 3.175mm 22T pinion gear

1 X 48P 3.175mm 23T pinion gear

5 X 48P Screws

1 X Screwdriver