The ventilation grille serves as an external grille of the hood and covers the ventilation ducts. The stainless steel ventilation grilles are made of brushed stainless steel, weatherproof and very robust. How they work: The ventilation grilles have a very high air flow. The hood protects against rain, cold air and insects. The stainless steel grille fits all standard round ventilation ducts and pipes. Wide range of uses: Suitable as ventilation flaps for kitchen hoods, bathroom fans, exhaust fans, air conditioning, clothes dryers, ventilation of living rooms, workshops, basements, offices and industrial facilities. The perfect choice for hobbyists and professionals. Easy one-person installation using standard tools: insert the socket into the ventilation duct and fix it to the wall with the screws provided. Note: Applicable to a 120mm opening