U.S. Scott 795 (2 copies) and 796 (2 copies) on 1937 Airmail Special Delivery Cover. The cover was mailed from Philadelphia, Pennsylvania to Washington, DC on November 22, 1937 and received in Washington on November 23rd. It also has a Philadelphia transit marking and N.Y. & WASH. RPO back stamp and a handstamped "DISPATCHED BY TRAIN TO AVOID DELAY" marking on the front.