antique architectural register grate large vintage steel floor vent grating

large antique vintage steel architectural floor register grate for heating, cooling and ventilation. This doesn't have any louvers or flow controls. It's just a standard steel grate.

It measures about 23 1/2" x 11 1/2" inside (as shown in the 5th photo) with an about 1 1/4" flange on the ends and a 1 1/8" flange on the sides for 26" x 13 3/4" overall.

This has a patina of age and rust.