Product DetailsName: Roof VentilatorZero consumption:Using natural wind and air-heat convection caused by the temperature difference between indoor and outdoor to drive the turbine to rotate,In this way, centrifugal force and negative pressure are used to discharge the stale air in the room.Material: 304 stainless steelSize: Diameter100mm/4in , 150mm/6in , 200mm/8in , 300mm/12in , 350mm/13.8in , 400mm/15.8in , 450mm/17.8in , 500mm/19.6in , 600mm/23.6in The mounting nozzle is slightly smaller than the vent pipe for easy installation, so please look at the dimensional drawings and choose the right size for you! Note:The product is measured manually and may have an error of 2-3cm; due to differences in light and screen, the color of the item may be slightly different from the picture.