3-1/4-inch by 10-inch, 26-Gauge galvanized steel exhaust cap with damper for use with a Zephyr 3-1/4-inch by 10-inch rectangular duct. Backdraft damper design prevents air from reverse flowing through the ducts. A built-in bird screen is included to help keep small animals from entering. Please check your Zephyr range hood's specification sheet to ensure compatibility.