Westinghouse brought quality to a whole new level when they introduced these lights in the 1920's.
The detail that separates these lights from the rest is not the amazingly clean condition, but the cast iron top that is sporting its original green paint along with the balance of the top, the HEAVY porcelain fitter.
These are 16 1/2 inch diameter porcelain covered steel. A process that makes a shade so durable, it could last for centuries. Any spots you see are simply glare.