1971, Lot of 13 mostly different "Officially used P.O. airmail test envelopes". From May through September 20, 1971, the U.S. Postal Service undertook an extensive test to evaluate the delivery time for an airmail letter to move overnight to its destination, if the letter was deposited by 4:00 PM and was not going beyond a 600 mile radius. The outer side of the envelope requested delivery time and gave instructions. Dealer's overall retail price amounts to $3,250. (M) (Image)

Start Bid € 270