Builder's Best 012635 Galvanized Steel Roof Vent Cap with Removable Screen & Damper, 4" Diameter Collar, Black. Speedi-Products 4-Inch Black Galvanized Flush Roof Cap with Removable Screen, Back draft Damper and 4-Inch Collar. Used for Exhaust Venting Systems. Can be used for Remodeling, Do it yourself and New Residential projects.
