42 In.H 42 In.W Non-Drnbl Alu Modular Louver Louver Type Stationary Blade Frame Type Hat Channel Frame Depth 4 in Mounting Style Flush Mount Outside Height 41 1/2 in Outside Width 41 1/2 in Rough Opening Height 42 in Rough Opening Width 42 in Louver Maximum Intake 3 876 cfm Maximum Exhaust 5 543 cfm Maximum Outside Width 41 1/2 in Minimum Outside Width 41 1/2 in Flange Width Not Applicable Free Area 5.4 sq ft Beginning Point of Water Penetration 709 fpm