A. Adjustable height to suit different installation requirements. Space saving top mounted type. B. Mushroom shaped roof exhaust fan can bring fresh air into the vehicle and prevent odours and gases from entering the caravan living space. C. Rated voltage: 12V; rated speed: 1800 rpm; rated air flow: 60CFM; mounting thickness: approx. 45mm - 140mm (1.8" - 5.5"); overall dimensions: approx. 145 x 103mm / 5.71 x 4.06", round opening diameter: 118mm (4.65"). D. When shopping, it is advisable to pay attention to the size and dimensions of the product to ensure it meets your needs. In the title and description, detailed information about the product, including its features and specifications, is provided. E. If you have any questions or concerns about your purchase, you can contact us. We will try our best to assist you. F. Thank you for choosing our product. We hope you like it!