The most expensive part in this assembly is the Cushion Assy,rear.
Parts such as the Rear Cushion: Seat, Spring, Damper Comp.,rear, Spring, Rr. Shock, Cushion Assy,rear are included in the Trx300ex Fourtrax 1998 (w) Usa Rear Cushion parts fiche.
With two applications this Nut,flange 12mm is the most specified part.