Square Ventilation Grille 150mm with Return Valve for Cooker Hood

our ventilation grille is made of stainless steel, our products do not rust, do not peel off, are corrosion-resistant and resistant to external environmental factors such as snow, rain, frost, and sunlight This 100mm ventilation grille is tilted 45° outward to prevent rainwater from entering, and is equipped with an internal return valve, which opens with the airflow when the fan is running and closes when it is off. It can effectively prevent insects, rain and cold air from entering; And there is a rubber ring on the return valve to prevent noise The rectangular ventilation grille has 4 fixing holes, simply lower the ventilation grille into the pipe or ventilation duct and secure it with the loop next to the ventilation grille, then the 4 rear screws to fix it to the wall (please wear gloves during installation) The set contains 1 adjustable ventilation grille, 1 screwdriver, 4 screws, total length: 185 mm, diameter of the retaining piece: 145 mm (for holes of approximately 150 mm in diameter) this outdoor vent grille is ideal for ventilation systems, air conditioners, kitchen extractor fans, and washing machine exhaust pipes. Be sure to ensure good ventilation and air circulation. Keep rats, flies and insects out of the area and maintain a good indoor environment.