[Low Noise Brushless Motor-Five times longer life than traditional brushed motors] : Exclusive brushless motor solution, working with ultra-low noise. Strong anti-interference, reduce the noise damage to the human body, provide a quiet and comfortable camper van space. High efficiency while ensuring low motor loss, the maximum load current is 4a, which saves the battery energy of your camper van and conforms to the environmental protection. [Independent Duct Design-Ceiling Fan Function] : It provides a level permanent air ventilation (when hatch is closed), letting the air circulate inside and outside your vehicle on rainy days. [Ultra Quiet Working Fan Blade and Strong Magnetic Net Screen] : With the patented curved surface and precise dynamic balance design, conforming to the principle of natural wind rotation, when the fan blade working, it reduces wind noise as much as possible, and realizes 4 noise levels of 10db, 25db, 45d, 68db. Dedicated vehicle-mounted strong magnetic Net Screen, easily disassembled and installed within two seconds, convenient to clean the fan blades, stable when driving and will not fall off. [Intelligent Rain Sensor and Reversible Ventilation] : The cover lid would automatically closes when it rains, without accumulating water and prevent rain leaking. Inhale or Exhuast, 4 speeds adjustable (3W/10W/20W/40W). [Universal Size and Lifetime After-sales] : It fits standard roof vent 14 x 14 inch, the suggested opening size is 360360mm, Recommended roof thickness: 37-85mm. High Powered with 12V voltage.