The backflow damper prevents the ingress of cold or warm air and wind from entering through the ventilation duct. The 4 inch Backdraft damper is made out of a Galvanized steel, the flap leaves are ...

Greenheck’s HB Series of Heavy Duty Industrial Backdraft Dampers includes the recently released HBR-150, a round industrial backdraft damper with a flanged-style frame. The HBR-150 is rated for ...