48 In.H 48 In.W Non-Drnbl GSteel Modulr Louver, Louver Type Stationary Blade, Frame Type Hat Channel, Frame Depth 4 in, Mounting Style Flush Mount, Outside Height 47 1/2 in, Outside Width 47 1/2 in, Rough Opening Height 48 in, Rough Opening Width 48 in, Louver Maximum Intake 5,484 cfm, Maximum Exhaust 7,834 cfm, Maximum Outside Width 47 1/2 in, Minimum Outside Width 47 1/2 in, Flange Width Not Applicable, Free Area 7.1 sq ft, Beginning Point of Water Penetration 709 fpm