Product OverviewMaximum Ventilators are CSA approved and do not need to rotate to prevent water or snow infiltrations, even withstanding hurricane wind and rain conditions of 175 km./hr. Its unique storm proof system prevents infiltrations, while at the same time capturing the wind from all directions and at velocities as low as 6 km./hr. With this combination of technology, wind and pressure differentials, a “chimney effect” results in drawing the stale air and moisture out of the attic space, while replacing it with fresh new air that enters through the soffits.