I am not sure how to classify this one. Following Elton's lead by putting the gutter tops in the porcelain category I have this one in my U files. Anyway, the top half is white porcelain and the bottom half is a green aqua glass. The two parts are held together by cement or a cement like material. I will post a separate photo of the marking. There is a plastic thimble in the pinhole. The insulator is about 6-1/8 inches tall. The top porcelain shell is about 7 inches in diameter and the outer bottom glass skirt is about 6-5/16 inches in diameter. The inner glass skirt is about 4 inches in diameter. It was a purchase off of eBay.