The Pin,spring,2x10 is the lowest priced item on this Rr. Brake Master Cylinder schematic.
Parts such as the Rr. Brake Master Cylinder: Plate,diaphragm, Hose Comp,rr Brk, Cup Comp,oil, Bolt,flange,6x25 are included in the Vt1100c2 Shadow Ace 1998 (w) Usa Rr. Brake Master Cylinder parts fiche.
In this schematic the "Washer,oil Bolt" is used most often.