A sample from the products for the Rear Brake Mastercylinder (cb600fa/fa3) include: Screw,pan,5x16, Cap,oilcup, M/c Sub Assy,rr, Joint,brk Rod.
On this parts fiche the Washer,oil Bolt is the most specified component.
The most reasonably priced component used on the Cb600fa Hornet 2009 (9) European Direct Sales / Abs Rear Brake Mastercylinder (cb600fa/fa3) is the Screw-washer,4x12.