I purchased this CD 102 with ground down top at the Mt. Dora, FL antique flea market some years ago. The main 'grind' area is round, and a bit tilted. There is additional grinding to the side of the dome, but that is not flat, more rounded. The body of the insulator has a lot of small scuffs running side ways. It may have been reused, either before, or after its use on a chair leg. Interesting, inexpensive piece.