Pipe backdraft damper with butterfly valve. Suitable for insertion into exhaust hoses or PVC. Ideal for bathrooms, garages, air conditioners, fans, extractor hoods, and ventilation systems. The flap valve opens and closes automatically, allowing only one-directional airflow and preventing cold air from entering. The inner rubber seal provides better tightness and noise reduction. Installation is by pushing the backdraft damper into the vent pipe as far as it will go. If installed horizontally, the spring position should be horizontal for optimum opening and closing; this also applies if installed vertically. The damper is made of PVC. The valve blades are PVC. The shaft and spring are PVC. The flame retardant material resists high temperatures exceeding 150 C. Use scenarios: - In a bathroom exhaust vent to block cold drafts when the fan is off. - In a kitchen or garage ventilation duct to prevent backflow from outdoor air. - In air conditioner exhaust or extractor hood systems to maintain one-directional airflow.