Protects internal fireplace and chimney from deterioration. Keeps out rain, birds, animals, and debris. Black powder coated galvanized steel. 24 gauge galvanized hood. 16 gauge galvanized wire mesh. 14 gauge galvanized braces. Stainless steel mounting brackets. Fits Rectangular: 8" x 8", 9" x 9", 8" x 12", 9" x 13", 12" x 12", and 13" x 13" outside tile sizes. Fits Round: 8", 10", and 12" outside tile diameters.