Early 1900s vintage cast iron architectural heating register grating for wall or floor. Measures 15 1/2" overall diameter, with a removable light steel cover plate in the center of the iron grating.
This has been painted many years ago (several times, by the look of it!). It's not marked that we saw, but possibly the lettering might be covered by the layers of old paint.
This has a lot of wear and chipping to the many layers of old paint, though the ironwork looks very nice, without chips or cracks. (That's the spring wire loops of the steel flue cover that show as 'lines' on the first photo.)