This is a beautiful sheet consisting of 4 stamps, issued by Guinea in 2006, displaying a variety of dirigible airships along with some of their inventors. Featured on the sheet are dirigible designer Alberto Santos-Dumont along with his famous "Number 6" dirigible at the 1901 German Dirigible Competition, airship inventor Ferdinand von Zeppelin along with his dirigible "The Zeppelin" pictured in Egypt, inventor Henri Giffard along with the first passenger-carrying dirigible, and chief engineer of "The Zeppelin", Dr. Ludwig Durr. The sheet is Post Office fresh, mint never hinged.