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