Check out any of the twenty-four Rear Brake Master Cylinder components enlisted.
In this schematic the "Clamp,oil Hose" is used most often.
Parts such as the Rear Brake Master Cylinder: Screw-wash.,4x10, O-ring,14.8x2.4, Plate,diaphragm, Joint,brake Rod are included in the Nsr125r 1989 (k) Sweden / Kph Rear Brake Master Cylinder parts fiche.