For sale: a special Thumb 5 string model from roundabout 1989-1991.
The bass is off-factory in colour "Metal sparley silver vintage white" according H.P. Wilfer himself, and is a one-off as far as I know (never seen one before!).
Sounds tight and is looking for a new owner. Interested? Testing is possible in Enschede, the Netherlands (close to the German border). Price: 1600 Euro.