Posthorn 1951, 10 ++ Z ++ 20 Pfg, horizontal se-tenant with lower margin and HAN "16006.51 1", in perfect condition mint never hinged, unsigned, unfolded, superb in every respect (choice copy), photo expertize H. D. Schlegel BPP (2019) "the se-tenant is genuine and has original gumming. The quality is perfect. "