When I got this piece I thought it was porcelain but it turns out to be a greenish white milkglass like the Maydwell CD 164's. It is made in China but is beautiful with an underlamp. Just goes to show even modern insulators have their beautiful sides. I'm surprised they made it out of glass and not porcelain. Transco was started in 1979 in South Carolina and was sold or merged to Ventex Technology Co. of Texas in 2014. Their products are made in China though. Go figure. Still neat items.