This 4" Diameter Supurr-Vent Louvered Hood is the perfect accessory for you dryer duct. The louvered hood is constructed to help prevent wind and rain from entering the vent. The louvered vent opens with ease for maximum airflow. The louvered vent hood snaps on quick and easy for installation. The louvered hood is weather resistant and has a melting point of 325° F+.