I had an opportunity to see this telegraph insulator in person and I took a dozen plus pictures. It has six wire groove/ridge projections with the following dimensions: 2 5/8" base diameter, 4 1/2" tall. It has a scattering of nicks and pings that you would expect with a very old insulator and a good heft. The base is smooth and the embossing sharp. The color is aqua. It takes a threaded wooden pin, which stops about half way through the threads.