Exhaust Fan Venturi Frame, For Blade Diameter 18 in, Includes Mounting Bolts, Slotted Motor Base, Overall Depth 9 in, Overall Height 22 in, Overall Width 22 in, Venturi Depth 3 in, Flange Width 1 in, For Cut-Out Height 20 1/2 in, For Cut-Out Width 20 1/2 in, Frame Finish Galvanized, Material Steel, Opening Diameter 20 1/2 in