1, 50 Rbl. on 15 Kopeks Workers, handstamped overprint in Type III (HZ 6 mm), horizontal pair from the left margin, the right stamp has an inverted overprint, a so-called Tete-Beche pair (inverted printing), extremely rare, in flawless mint never hinged condition, unsigned, photo certificate Walter Zirath BPP (2025) "These stamps are among the greatest rarities of the German occupation issues during World War II.", Michel 14,000.- Only about four pairs of this type are known to exist so far!