Miami Tech GRV4XTDS - Galvanized Roof Vent, 4", 26 Gauge, Extra Tall With Damper And ScreenProduct Features: Galvanized steel provides excellent corrosion resistance and longevity. Bird screen standard on all roof vents, unless ordered with damper. Sealed seams keep out the elements. Flanged base provides for good vent-to-roof contact and easy caulking surface.