A Fletcher NO. 3 "Jumbo" wire holder. It appears to be made of brass instead of cast iron. The porcelain split ring spool has a ¾ inch dia hole. It is 2 inches tall and has a diameter of 2 inches at the widest dimension (the flange at each end). The metal bracket is Marked "PAT'D / /au0g 18 / 1887. The metal casting is 1 and ¼ inches wide. The lag screw is 1 5/8 inches long and ¼ inch dia. at the base.