What is the purpose of the expanded outlet

Does this include the bearing assembly

unusual noises during the heating cycle

Does this part include the O-ring or seals

ZoneFirst SPRD-14 Damper R-22 What is the purpose ofThe ZoneFirst SPRD 14 Damper is a 14 inch round barometric static pressure regulating damper designed for high performance HVAC zoning. In a multi zone system, as individual zone dampers close, duct static pressure naturally increases. This barometric relief damper utilizes a single blade, counter balanced weighted arm to automatically compensate for this excess pressure, preventing coil freeze ups and high limit trips. Specifically engineered for