I've had these unique strains and keep adding as I come across them. These strains were patented by Thomas C. White of St. Louis, MO. I love the embossings on these and even though the colors are usually shades of brown, they can have some attractive colors. Most of these pieces were manufactured by Square D. Co.and probably Thomas Insulator Co. This cylindrical style was patented on Jan 20, 1914 number USD45172S. Another neat fact is T.C. White came up with the catalog numbering system that was used up until modern times by most insulator manufactures and jobbers. It ran from 500 to 506,600's, 800's etc. These shown are marked Whites 502,504 and 506. I have yet to find a 500 whith this marking. Some have the Square D Co. contract logo on the back.