i left my phone number with an antique dealer in the area who said he had 5 multipart insulators for sale, but they were buried under the snow. he called me up over the week and i stopped by yesterday and this was one of the 5 waiting for me. its an OB two part with a nice black/muddy brownish glaze, but i don't have the slightest clue to the M# or possible value, so if anyone has either of these pieces of information it would be greatly appreciated