Durable material: Ventilation grille made of 304 stainless steel, polished surface, corrosion-resistant, sturdy and durable. Size: The round vent has a diameter of 125 mm (5 inches), 4 drill holes (3.5 mm), easy to install; and the air volume is adjustable according to your needs. Adjustable ventilation: Our supply air can be used for indoor ventilation. Suitable for heating or ventilating a boat, motorhome, or caravan, adjustable ventilation, fresh air exchange according to your needs. Designed for: Our round ventilation grille is professionally designed for yachts, boats, motorhomes, roller shutters, and ventilation panels, ideal for raising and improving air circulation. Wide application: The round ventilation grille can be used indoors and outdoors for anyone who needs adjustable ventilation. Heat can be generated depending on the food being grilled. Even garages can be used.