Airmail, 1933, 50¢ "Chicago" Zeppelin, top plate number "21171" block of six, remarkably well centered throughout, fresh never hinged o.g., an Extremely Fine gem, this is the finest top plate block we have ever offered in this pristine condition; with 2004 P.F. certificate. Scott No. C18  $725. $0 (Image)

Airmail, 1933, 50¢ "Chicago" Zeppelin, bottom margin plate block of 6, o.g., never hinged, some gum creases, otherwise fresh and Very Fine. Scott No. C18  $725. $0 (Image)