For sale is a First Day Issue 1991 William T. Piper Stamped Envelope. This item features an aviation theme with multi-color design and is mint hinged. It was canceled as a First Day of Issue and is ungraded and uncertified. The envelope was originally produced in the United States and falls under the Stamps, United States, Covers, and FDCs (1951-Now) categories. Perfect for stamp collectors or aviation enthusiasts, this unique piece is a great addition to any collection.