The Rear Brake Caliper is made up of components including this Caliper Assy, Rear 2 which is the most expensive.
The twelve Xt660x 2004 1d23 England 1c1d2-300s3 Rear Brake Caliper component parts are all listed in this schematic.
A sample from the products for the Rear Brake Caliper include: Brake Pad Kit 2 (nas), Bolt, Support, Pad, Pin, Pad.