3 In. to 4 In. Roof Vent Kit for round Duct Steel in Black
Roof Vent Kit for round Duct Steel in Black. It is compatible with 3″ or 4″ ductwork and includes a 3″ to 4″ adapter for convenience. Not suitable for dryer venting. Mounting Position Roof Mount. For roof ducting of fans with a 3 or 4 in.