Of all the components that make up this Rear Brake Caliper(cb1000 R) the O-ring,2.5x1.5 has the lowest price.
The sixteen Cb1000r 2010 (a) England / Mph Rear Brake Caliper(cb1000 R) component parts are all listed in this schematic.
Of all the components used in this assembly the Caliper Sub Assy, is the most expensive.