This pic shows a Knox porcelain cabletop mounted on top. I don't know whether it was seated in a cavity, or if it was on a pin. Reference previous pic [id=80882156] to see same unit without the insulator on top, and with the metallic 'decoration' . Please post any info to ICON and/or to me at the email above the pic. My hunch is this has nothing to do with an insulator configuration.