This is a vintage Whitall Tatum insulator # 9, embossed "made in the USA" circa 1922 to 1938. The vintage insulator was intended as an insulator for telegraph or "personal communications" lines. Whitall Tatum of Millville, NJ, mass produced insulators during that time frame until it was bought by Armstrong, and later Kerr. The clear glass insulator is marked with a W over a T inside an inverted Triangle. My father found this antique insulator on an old telegraph line running along an abandoned railroad track more than 40 years ago. The vintage insulator is in beautiful condition, free from breaks or cracks. Clarity is wonderful and embossing is still sharp. The old telegraph insulator measures about 3.5" tall and 2.25" wide.