This is a 87 Tooth 48 Pitch Spur Gear for electric HPI vehicles.
This is the main gear of the vehicle and it meshes with the pinion gear.
Black in color
One 87T spur gear
One gear ratio chart
Installation onto vehicle.
Outer diameter: 46.8mm (1.845")
Thickness: 5mm (0.20")
Number of teeth: 87