The Washer,plain, 6mm is the lowest priced item on this Fuel Tank schematic.
Some items from this specific schematic: Nut,flange,6mm, Set Illust*type3*, O-ring,39.5x5, Syay A,fuel Tank.
The forty-eight Cb1300a 2008 (8) European Direct Sales / Abs Fuel Tank component parts are all listed in this schematic.