American Aldes Standard Dryer Wall Hoods are engineered to accommodate high airflow pressure and velocities found in dryer vent systems. All Standard Dryer Wal hoods have gravity dampers. Each Dryer Wall Hood is designed to maximize airflow and minimize noise. The magnetic-catch damper ensures a tight closure when the fan is not running and eliminates damper flutter in windy conditions. These hoods should be used when backdraft dampers are not present at other locations within the duct system. Dryer Wall Hoods are available in heavy-gauge galvanized steel, stainless steel, or copper.