Owens Corning Ventsure Black Plastic Continuous Unfiltered Ridge Vent 20 ft. L x 11.25 in. WOwens Corning brings you Ventsure, the Continuous Unfiltered Ridge Vent to allow the outside air to flow upward and out of the attic. Heat and moisture collection can lead to ice damming, roof deterioration, and mold infestation. The ridge vent roof system helps prevent moisture from becoming trapped in insulation, structural wood, and shingles. It helps airflow through the attic to manage temperature and humidity, thus preventing damage and premature