Check out any of the seventeen Taillight (km100-a6/a7) components enlisted.
The Washer-plain,6mm is the cheapest item from this partsfiche.
Parts such as the Taillight (km100-a6/a7): Tail Lamp, Bolt-upset, Washer-plain,6mm, Damper are included in the Km100-a1 1976 Usa Canada / Mph Kph Taillight (km100-a6/a7) parts fiche.