ground Aldes the Prime Minister backdraft damper solution favored for residential, moneymaking and industrial installations around the world. The highly rated self-moving backdraft damper a full seal, with no leakage to prevent backdraft airflows. It has been for unrefined pressure drop and to require almost zero pressure to unresolved the damper flaps when air is smooth the redress direction. The integral assembly into the ductwork for easygoing installation and prevent leakage. in 4 '', 5 '', 6 '', 7 '', 8 '', 10 '', 12 '', 14 '' and 16 ''.