65c - $2.60 Graf Zeppelin, set of three on 2c Sesquicentennial Exhibition entire, tied by "Washington D.C. / Apr 19 / 5PM / 1930" duplex, dual United States and Germany flight cachets, with small circular "This Article Made the Complete Round Trip / Via Graf Zeppelin" handstamp, with Friedrichshafen (6.6.30) and New York (Jun 8) backstamps, light uniform toning, a rare flown Graf Zeppelin first day cover; with 1996 Philatelic Foundation certificate.