27 In.H 33 In.W Drnbl Extrd Alu Intake Louver Louver Type Stationary Blade Frame Type Flanged Frame Depth 4 in Mounting Style Surface Mount Outside Height 23 1/2 in Outside Width 29 1/2 in Rough Opening Height 24 in Rough Opening Width 30 in Louver Maximum Intake 2 326 cfm Maximum Exhaust 3 326 cfm Maximum Outside Width 32 1/2 in Minimum Outside Width 32 1/2 in Flange Width 1 1/2 in Free Area 2.5 sq ft Beginning Point of Water Penetration 1 031 fpm Maximum Air Velocity 3500 fpm