Durable Material: Air Vent Made from 316 stainless steel material, polished surface, corrosion resistance, sturdy and durable to use. Size: Round Air Vent is 125mm(5inch) tall diameter, 4 drill holes(3.5mm), easy to install; and the air volume is adjustable to meet your need. Adjustable Ventilation: Our Incoming air can be used for indoor exhaustion. suitable for heating or ventilating a boat, mobile home or caravan, Adjustable ventilation, fresh air change according to your needs. Application: The round ventilation grille can be used indoors as well as outdoors for anyone who needs adjustable ventilation. Heat can be generated depending on the food being grilled. Even garages can be optimally ventilated with these ventilation rosettes.