The lowest price component in this Rear Brake Caliper parts-list fiche is the O Ring.
On this parts fiche the Bolt,hex.,6x12 is the most specified component.
Parts such as the Rear Brake Caliper: Screw Bleeder, Spring,brake, Piston 34x28, Pin Set,hanger are included in the Cb500s 2002 (2) Germany / 37k Rear Brake Caliper parts fiche.