Shingle Vent II Roof Vent System ~ New in open box... Purchased new for an out building but never used. 10pcs - 48" x 18" good for up to 40 foot run. *** If the ad is up - then it's still available *** Fire rated for Class A roof decks. Advanced design of other Air Vent ridge vents including the external baffle and internal weather filter for superior airflow performance and weather protection. For enhanced ridge cap shingles, cedar shake, cedar shingle and tile applications. 18 square inches of net free area per linear foot. Built-in external baffle deflects wind up and over the ridge enhancing airflow performance. Internal weather filter provides protection against weather and insect infiltration. Less than 7/8 inches tall on the ridge making them virtually invisible from the ground.