I was just looking through Jack Tod's book compiling the patents related to insulators and found this one yesterday. This piece is from Canada and my Canadian friedns indicate that it was used there. It is basically a metal skirt that wrape the insulator to protect it from projectiles hurled at it. Perry J. Bott of Little Rock Ark is the inventor credited with this invention. If you ever studied geology you will encounter the term 'Canadian Shield" which is the parent bedrock area south of Hudson Bay. So I have coined this invention the Canadian Shield. $38 shipped to you.