Even with its clear manufacturer's marking, we struggled to discover much about this rare piece, however we believe this is an original WWII U.S. Army Air Corps/Force pilot's document case, intended to be tucked into a larger briefcase. It was manufactured by The Leather Specialty Co. and its official nomenclature is the "Envelope, Leather, Type III, Class B, Style 4, Stock No. 8450-296-6900" from the "GS- 00S56707" contract. It is in very good condition, with retractible handles, and a well-functioning Conmar-branded zipper.