5/8" wide in enamel on silvered brass with reverse threaded post and screw cap. There are two faint hairlines in the white enamel but barely visible without magnification. Durant was the owner of Buick and founder of General Motors in 1908. He lost control in 1910 but remained active in the industry subsequently founding Chevrolet in 1911 with Louis Chevrolet. Profits from this venture permitted him to regain control of GM in 1916 at approximately the same time he assembled United Motors which was integrated into GM on December 31, 1918. Some of the United Motors holdings including ball bearings maker New Departure, Dayton Engineering Laboratories Company, later known as Delco, and others. A rare historic piece that still displays Exc.