...Either that, or this large post type insulator was salvaged from a pole ruined in an accident or downed in a storm. I found it at an kitschy vintage shop yesterday. I later arrived home $10 poorer and 1 big heavy HV post insulator richer. This grey post insulator will make a great mate for the brown post I'm getting from a fellow ICON member in the near future.
The uppermost umbrella is inkmarked with CHANCE 2800 / TYPE F NECK / 7 5 77 at the 6:00 position, and something-150 (the "something" is not recognizable) at the 9:00 position. There are no visible markings on the metal base, and the base is threaded for a remarkably small bolt given the size and weight of this insulator.