21 Tooth Transmission Sprocket. Fits 4spd Sportster 1984-90.

* CNC machined from high grade steel.

* Maximum spline-to-shaft contact.

* Heat-treated for long life and extended wear.

* Nickel plated for corrosion & wear resistance

* Manufactured in USA.

Use with O-Ring Chain # BC-19-7286 & Clip Link # BC-19-7303