The component with the lowest price in the REAR BRAKE CALIPER(CB600F /F3) schematic is the O-ring,2.5x1.5.
Parts such as the Rear Brake Caliper(cb600f /f3): Retainer, Piston, Pin,hanger, Pad Set,rr (nas) are included in the Cb600f Hornet 2009 (9) European Direct Sales / 25k Rear Brake Caliper(cb600f /f3) parts fiche.