Intake Louver Fixed Drainable 18H x 48W

21 In.H 51 In.W Drnbl Extrd Alu Intake Louver Louver Type Stationary Blade Frame Type Flanged Frame Depth 4 in Mounting Style Surface Mount Outside Height 17 1/2 in Outside Width 47 1/2 in Rough Opening Height 18 in Rough Opening Width 48 in Louver Maximum Intake 3 101 cfm Maximum Exhaust 4 435 cfm Maximum Outside Width 50 1/2 in Minimum Outside Width 50 1/2 in Flange Width 1 1/2 in Free Area 2.8 sq ft Beginning Point of Water Penetration 1 031 fpm Maximum Air Velocity 3500 fpm