Revolution (REV-11 and REV-9) are the only truly "Green" ridge vent available. The 11-inch and new 9-inch wide by 20-foot long plastic vent core is made entirely from the same polypropylene plastic used to manufacture all of Cor-A-Vent's other products. We meticulously capture the excess scrap during production, reprocess it and feed it directly into the Revolution, keeping it out of landfills while also reducing the use of petroleum needed for new plastic production. Revolution's precisely spaced ventilation channels provide 12 square inches of Net Free Vent Area per lineal foot to promote the removal of damaging moisture and heat from inside your attic. This helps reduce heating and cooling loads when used in conjunction with balanced intake ventilation. The simple, yet highly effective structural design of Revolution supports power-nailability for easy installation on asphalt shingle roofs, while also providing protection from rain, snow & insects.