Louver Wall Opening 18x18In Galvannealed

18 In.H 18 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 17 1/2 in Outside Width 17 1/2 in Rough Opening Height 18 in Rough Opening Width 18 in Louver Maximum Intake 744 cfm Maximum Exhaust 1 063 cfm Maximum Outside Width 17 1/2 in Minimum Outside Width 17 1/2 in Flange Width Not Applicable Free Area 0.9 sq ft Beginning Point of Water Penetration 709 fpm