“Day 29: This is a single note set issued in 1921 by a well-known interior designer in the city of Hamburg named Gustav Dorén. In the place where you would normally find the serial number on a piece like this, there is instead the word "Probedruck", which basically means "test print" or "specimen".
The note has a denomination of 75 Pf.
Due to the fact that this note is a specimen or test print, and it is not listed in any of the Notgeld catalogs that I'm aware of, I would estimate the value somewhere around $100+. The standard issue note, with a serial number, catalogs between $40 - $50.”