Adjusts air flow in individual runs of round pipe Durable galvanized steel construction Can be installed in a new or an existing duct run Master Flow Dampers balance and adjust the air flow in individual runs of round pipe in HVAC systems. Our In-Line dampers make it easy to install in an existing run of pipe. It can be installed in a new or an existing duct run. #N/A Type Air Admittance Valve Brand Master Flow MPN Does not apply UPC 050206035788 EAN 050206035788 .