These are included when you purchase a slipper clutch, a clutch hub or a complete clutch kit from us, but are NOT included if you just purchase a clutch basket.
The serrated washer is a use once only item. Ducati recommend that this is replaced whenever you undo the clutch hub retaining nut.
The serrated washer sits under the central clutch hub retaining nut. To replace the clutch basket you will need to remove the clutch hub.