This is an optional Team Losi Racing Aluminum 48 Pitch, 20 Tooth Pinion Gear, and is intended for use with most Team Losi Racing 1/10 scale vehicles. This pinion can also be used with any 1/10 vehicle that uses a 48 Pitch pinion gear. This pinion gear has been machined from high quality aluminum, and hardcoated for durability. This package also includes a set screw.