20 Fen postal stamp with dark red purple overprint "Zawierce", variety "double overprint at the upper stamp margin", unused with original gumming, in this variety is it the first known copy - the edition of this stamp in type I amounts to only 85 pieces - it is one of the large rarities of the collection areas, photo expertize Petriuk (2018) : " . . . . Me is no second copy with a double overprint above known. "