U.S., Scott #C23 used on 1938 U.S. Air Mail Week cover/reply card, May 19, 1938, sent from Estherville, IA, to Honorable Franklin Delano Roosevelt, President of the United States, Washington, D.C. This scarce item is from the Franklin D. Roosevelt Collection (with H.R. Harmer handstamp).  Included inside is a green Estherville, Iowa, label to be used to seal the return card. See scans/photos for contents and exact condition. Free U.S.P.S. insured shipping to any U.S. address.