California Clay Products (CALCO), So. Gate, CA 1923-1932
Also know as grills or ventilation tiles, these were originally designed for use in the transfer of heat, for stoves or fireplaces. And they were also used in attics or foundations to let air thru. These were made by CALCO and have their signature mottled glazing.
5 3/4″ x 1/2″ thick
Qty = 4 pcs