The Honda PILLION*PDBG/PBK* has three products enlisted in the schematic.
On this parts fiche the Nut,u.,6mm is the most specified component.
Parts such as the Pillion*pdbg/pbk*: Pillion Seat Kit Alc, Nut,u.,6mm, Stay Kit are included in the Cb1000ra 2009 (9) France / Abs Cmf Pillion*pdbg/pbk* parts fiche.