Early 1900s vintage cast iron architectural heating register frame, a grating for wall or floor. Measures 15 3/4" overall diameter, 6 1/4" across the center opening, and 14 3/4" between the two holes for mounting.
This has been painted many years ago - it's not marked that we saw, but possibly the lettering might be covered by the layers of old paint. The ironwork is in very good condition, without chips or cracks.