Durable Material:The body and the flap blade are made from galvanized metal material, a durable material for long-lasting performance. Constructed with sturdy components to ensure reliability.Size: Port Outer Diameter: 100mm / 4"; Length:155mm / 6.1 inchManual Airflow Adjustment: Enjoy a comfortable environment with our damper sleeve, designed to use the manual handle on the valve to adjust the air volume from multiple angles. This is helpful to control room temperature and stop the backdraft. It is also important to know that the damper sleeve should be installed in places where you can easily control the handle.Good for Air Balancing: The backdraft damper does not provide a completely airtight seal, and its purpose is to balance air rather than terminate it.
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