Over the past few months I have had several copper-plated U-1743 and 1692 pieces discovered in Holland in the basement of a house under renovation. In my opinion these are very unique insulators and the process of coating them with copper still intrigues me. The one in the picture had a damaged copper jacket due to wire friction and my curiosity "what's underneath" finally won, I removed the copper sheet except for the top part and this was the effect, a beautiful colored patina on porcelain after many years of contact with copper, thank you for watching.