Soler and Palau RCXII12SFS Gravity Exhaust Ventilators Aluminum RCXII Gravity Relief Intake Ventilator Exhaust Fans RCX Collection 12" RCX Gravity Ventilator Self FlashingRelief and intake ventilators are used to exhaust (relief) or supply (intake) air from or to an enclosed area without the need for a power operated fan They rely on a difference in static pressure inside and outside the area to create an air flow through the ventilator from the area of higher pressure to the area of lower pressure If the enclosed area is under a negative pressure air will flow into the enclosed area (intake) If the enclosed area has a positive pressure air will flow from it to the outside These units can also operate as gravity ventilators allowing air to flow from an enclosed area using the Â"Stack EffectÂ" The amount of air flow will depend on the temperature difference inside and outside the area and the height difference between the ventilator and the outside air intake to the area Features:Diameter: 20"Length: 24"Height: 16"Low Contour Spun Aluminum Hood for Attractive AppearanceAll Heavy Gauge Aluminum ConstructionWeather Resistant Design for Long Life and Maintenance Free OperationGalvanized Bird Screen is StandardShipped Completely Assembled for Ease in InstallationSoler and Palau is the worldÂ"s leading fan manufacturer Their extensive range of residential and light commercial fans offer the ideal solution for air movement in any domestic application or office environment Soler and Palau products can be found in virtually any commercial or residential application ranging from innovative quiet and reliable room ventilators to large diameter high capacity exhaust systems designed for critical applications in some of the world s toughest environments