The Seat assembly is constructed from several parts from which the Double Seat Assy is the most expensive.
Some items from this specific schematic: Cover, Seat, Nut, Flange(34m), Double Seat Assy, Screw, Pan Head(3js).
The most reasonably priced component used on the Fj1200a 1992 4bs4 Europe 223xw-300ea Seat is the Washer,spring.