The most reasonably priced component used on the Gsf600s Bandit 2002 (k2) Usa (e03) Rear Caliper is the Bolt.
Parts such as the Rear Caliper: Spring, Piston Set, Cover, Bleeder are included in the Gsf600s Bandit 2002 (k2) Usa (e03) Rear Caliper parts fiche.
Check out any of the fourteen Rear Caliper components enlisted.