This is a most interesting display card which shows the Zeppelin LZ 4 over Mannheim on 4 August 1908. It has a postage stamp showing Ferdinand Graf Zeppelin and one of his zeppelins. It also proclaims that the stamp was issued by theDeutsche Luftpost and cost 3 Reichs Marks. This stamp may come from the Third Reich era. I believe Marks in Germany after 1945 were referred to as Deutsche Marks (D-Marks). The card measures 4 1/4″ x 6,” while the stamp itself measures 1″ x 1 1/4.” This collector’s card is serial numbered on the reverse.