With two applications this Nut Hex Cap,6mm is the most specified part.
Parts such as the F-26 Taillight: Bulb (12v21w-5w), Bracket,taillight, Nut Hex Cap,6mm, Cord,tail Light are included in the Cbx250rs 1984 (e) England F-26 Taillight parts fiche.
The F-26 Taillight is made up of components including this Taillight Unit which is the most expensive.