The Eco Plus Backdraft Damper attaches to inline ventilation systems to keep exhausted air out for good. When used in conjunction with a fan and carbon filter, the Backdraft Damper also helps control odors as it prevents any untreated air from escaping the enclosed area. The directional damper installs downstream from the fan: when the fan turns on, the airflow opens the damper, and when the airflow stops, the damper closes. This six-inch Backdraft Damper fits any standard six-inch ventilation ducting.
— Ships from Portland, Oregon USA.