The component with the lowest price in the REAR CALIPER (MODEL K5/K6) schematic is the Washer.
On this parts fiche the Bolt(6x10) is the most specified component.
Parts such as the Rear Caliper (model K5/k6): Bolt(6x10), Seal Set,piston, Guard,rr Calip, Boot are included in the Rm250 2002 (k2) Usa (e03) Rear Caliper (model K5/k6) parts fiche.