CHIMNEY CAP – 24 Gauge single piece galvanized steel hood. 18 gauge 3/4 expanded galvanized steel mesh. 14 gauge galvanized steel base for extra strength. Slotted hex head mounting screws. Attractive black powder coated paint finish. Outside mounting provides greater free air space for better dealt. Prevent certain kinds of downdrafts. Keep out birds, squirrels and animals. Keep out leaves limbs and debris. Arrest sparks and help prevent fires. Protect flue from moisture.