The Vents ventilation flange is designed to connect to aluminum, PVC or soundproofed ductwork. The Vents brand has developed this 125mm diameter check valve to prevent reverse airflow in ventilation systems.
When your ventilation system is switched off, the automatic check valve will prevent air from circulating in the ventilation ducts. The air flow will open its aluminum blades and close them again thanks to their spring. During installation, the damper blades must be positioned vertically.