Sirr0und Ondura 4Pk Vented Closure Strip For use with the Ondura Corrugated Asphalt Roofing System. Vented closure strips are used to close off Ondura’s corrugations while providing additional ventilation. Allows surface airflow between the corrugations when additional ventilation is desired. Recommended when applying Ondura over existing roofing (installed at the eave and ridge). Do not use when a watertight seal is required, such as in valleys. Do not use with Ridgeline ridge vent. 44″ long. 4-pieces per package. MPN# 702 SKU# 121088UPC# 756541007021