On this parts fiche the Nut,u.,6mm is the most specified component.
Parts such as the Pillion*pdbg/pbk*: Pillion Seat Kit Alc, Stay Kit, Nut,u.,6mm are included in the Cb1000r 2011 (b) European Direct Sales / St Pillion*pdbg/pbk* parts fiche.
The Pillion*pdbg/pbk* is made up of components including this Pillion Seat Kit Alc which is the most expensive.