Back-Draft Damper Description Description It directs the air flow by opening and closing according to the air flow direction. Square and circular models are available Related products Air Handling UnitsKitchen AspiratorsUnit SeriesKITCHEN ASPIRATOR Air Handling UnitsFAN SERIESAXIAL WALL TYPE FAN Air Handling UnitsCompact Type Roof-Top UnitUnit SeriesCABINET TYPE FANS WITH EC