Feature 1Sturdy Material: Made of engineering grade ABS material, this ventilation fan is weather resistant, high stability, and impact resistant, ensuring durability and longevity in various outdoor environments. 2Practical Design: With a 340 x 340mm opening size and stainless steel mesh screen, this roof vent fan is effective in preventing debris from entering your vehicle. 3Water Resistant Sealing: Equipped with sealing strip and stainless steel support rod adjustable from 0 to 31.5 degree, this fan ensures a water resistant sealing and provides ventilation at any angle. 412V Single Way Fan: Featuring a 12V single way electric exhaust fan, this air vent fan accelerates air circulation in your vehicle, ideal for installation in bathrooms, kitchens, warehouses, and lounges. 5Versatile Use: Ideal for repairing damaged or leaky vehicle roofs, this roof ventilation exhaust fan is suitable for marine, boats, yachts, RVs, trailers, and motorhomes, promoting air circulation while fixing leakage.Item Type: RV Roof Vent FanInstallation Opening Size: Approx. 340 x 340mm / 13.39 x 13.39inFan Outer Size: Approx. 420 x 420 x 134mm / 16.54 x 16.54 x 5.28inSuitable Installation Thickness: Approx. 20-55mm / 0.79-2.17inFunctions: Exhaust only, white top cover to block sunlight from entering the interior(If the top of your car leaks or there is a local leakage, this fan can be used as a repair part to install in the damaged location, providing ventilation conditions inside the car and also repairing the leakage)Application: Suitable for installation in large transportation vehicles such as RVs, motorhomes, buses, yachts, etc., quickly exchange indoor and outdoor air, providing refreshing air for your cabinInstallation Steps:1. Determine the installation position and mark it2. Use a hole cutting tool to drill a hole with a size of 340 x 340mm3. Place the exhaust fan into the drilled hole and connect the circuit4. Install the fixing clamping frame and secure with screws to complete the installation Package List1 x Roof Vent Fan1 x Knob1 x ScrewNoteThe opening direction of the exhaust fan must be opposite to the direction of the car's front end. If not installed properly, the airflow may lift the cover of the exhaust fan during high speed driving, causing damage. This issue does not belong to the product itself.