On this parts fiche the Washer(10x15x1.5) is the most specified component.
A sample from the products for the Rear Master Cylinder include: Connector, Hose,rr Reservoir Tank, Tank Assy,reservoir, Screw.
This part-list fiche shows all the components that make up the Gsf1200s Bandit 2001 (k1) Usa (e03) Rear Master Cylinder .