I was hoping some collectors out there could help me out with this insulator. I believeit to be a CD 263.........however, it seems to be a cross between a 263 and a 264. I has Columbia on the front and also has the 1890 patent date, but it is either blotted out or so poorly embossedthat you cannot see it. What's getting me is the dimensions. It is 4 inches across........but is only 4 and 7 8th's high(which depicts a CD 264). I've checked and double checked it. I'm also getting these dimensions out of the new price guide. Can anyone enlighten me as to what the deal is with this one?