American Aldes delivers the premier backdraft damper solution favored for residential and commercial installations around the world. The highly rated backdraft damper provides a complete seal, with no leakage to prevent backdraft airflows. It has been designed to provide almost zero pressure to open the damper flaps when air is flowing the correct direction. The entire assembly inserts into the ductwork for easy installation and prevent leakage. Available in 4", 5", 6", 7", 8", 10", 12", 14" and 16".