10-Inch Circular Inline Backdraft Damper - Butterfly Action Draft Shutter, 250mm - Airflow Control

8-Inch Circular Inline Backdraft Damper - Butterfly Action Draft Shutter, 200mm - Airflow Control

4-Inch Circular Inline Backdraft Damper - Butterfly Action Draft Shutter, 100mm - Airflow Control

5-Inch Circular Inline Backdraft Damper - Butterfly Action Draft Shutter, 125mm - Airflow Control