This schematic depicts all components used in the St50 Dax 1982 (c) General Export (kph) Rear Cushion (st50c) partslist.
Some items from this specific schematic: Washer,plain,12mm, Case,cush*yr-26*, Washer,10mm, Damper Comp.,rr..
With three applications this Nut, 10mm is the most specified part.