This piece is 3" tall with raised image of "U.S. Navy/ZRS-4" airship at center. The silvery metal is unmarked but appears to be Duralumin, an aluminum alloy used in the construction of airships. Additional text on the item reads "ZRS-4/Ring Laying/Goodyear Zeppelin/Akron, Ohio U.S.A. Oct. 31, 1929." The company was contracted by the U.S. Navy in 1928 to build airships and this was the first ship built and then named USS Akron. At the ceremony in October 1929 these disks were given as souvenirs to some 400 guests attending the ceremony when a gold rivet was driven into the master ring of the rigid framework forming the ship. Bottom edge has hairline .25" bump on the side but otherwise very little wear. Back of the piece carries the name of maker "Meyer & Wenthe, Chicago." Rare and the only example we've seen. Exc.