1 Mark large inland service with a double, red overprint "Danzig". The second overprint is offset by approximately 0.3 mm upwards and to the left, with minimal changes to the original stamp color and gum structure due to solvent influence, very well perforated, mint condition with original gum, signed Z. Mikulski, Star, Hochkeppler, Ruberg and H. S., expert opinion by Z. Mikulski AIEP and certificate by Volker Erdwien BPP, the changes on the stamp are still acceptable considering its rarity, only one sheet (20 examples) is known, Michel 5. 000.-