I love these pieces. Just the shape of them makes them attractive. These are Louis Fort Insulators. I was fortunate enough to aquire two different styles of them. The first one is the D model with a bigger hole. the second is a E model which used a standard wire hole. It is also less beefier and lighter insulator. Both of these fall under patent US 1,240,330- 9/18/1917 for streetlight applications. I've seen some of these in attractive colors of brown but have no idea as to who made the porcelain parts for Louis Fort Co.