28 In.H 22 In.W Non-Drnbl GSteel Intake Louver Louver Type Stationary Blade Frame Type Flanged Frame Depth 4 in Mounting Style Surface Mount Outside Height 28 in Outside Width 22 in Rough Opening Height 24 in Rough Opening Width 18 in Louver Maximum Intake 1 750 cfm Maximum Exhaust 2 500 cfm Maximum Outside Width 34 in Minimum Outside Width 22 in Flange Width 2 in Free Area 2 sq ft Beginning Point of Water Penetration 766 fpm Maximum Air Velocity 3000 fpm Blade Angle 45 Degrees