3 R on 20 Kop. workers black yellow green, overprint in type III (swastika 4 mm), horizontal strip of three! cancelled by Cyrillic cancel, in of the upper perforation by two stamps slightly shorter perforation, the other condition is sound, multiples of this stamp are extremely rare, signed Pickenpack et alia, photo certificates Werner Pickenpack BPP (1971) : " it is the so far only me known strip of three of the number 9. " and Walter Zirath BPP (2025) "the strip of three is very rare. ", Michel 5.400.-