Round six-inch (152mm) diameter, fresh air damper with 24-volt/AC powered-open/spring-closed motor used for fresh air intake for ventilation or for combustion makeup air. Adjustable damper position range stops. Single-blade damper. Galvanized steel. Quiet operation. Can be field-converted to power closed/spring return open damper. Blade closes off tightly against gasket for minimal leakage. Male (crimped) and female (uncrimped) ends to connect to any rigid or flexible round duct.