Durable Material:The body is made from stainless steel material and the flap blade is made from aluminum, durable material for long-lasting performance. Constructed with sturdy components to ensure reliability.Size: Port Outer Diameter: 100mm / 4 inch; Length:160mm / 6.3 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.Edge Silicone Sealing: Our damper sleeve features a rubber seal ring inside, providing good air tightness and it can prevent the air duct valve from leaking when it is closed.