The Maximum Ventilators do not require to rotate to prevent water or snow infiltrations. Its unique storm proof system checks infiltrations while simultaneously catching the wind flow from all directions and at wind velocities as low as 6 km/hr (4 mi./hr.). With this combination of technology, wind, and pressure differentials, a “chimney or vacuum effect” results in drawing the stale air and moisture out, thus preventing moisture & heat buildup within the attic space.
For structures with restricted air intake, this product has been specifically engineered to provide the required amount of intake for a properly balanced attic.
Maximum ventilators 301,302, and 303 work on two principals, the Venturi and Bernoulli effect providing superior ventilation without the need of mechanical assistance.https://www.ventilation-maximum.com/en/sloped-roof-ventilators/