Dayton Louver,Adj w/ 28 to 46 In,Aluminum 2FTV4

18 In.H 28 In.W Non-Drnbl Alu Intake Louver, Louver Type Stationary Blade, Frame Type Flanged, Frame Depth 4 in, Mounting Style Surface Mount, Outside Height 18 in, Outside Width 28 in, Rough Opening Height 14 in, Rough Opening Width 24 in, Louver Maximum Intake 1,565 cfm, Maximum Exhaust 2,240 cfm, Maximum Outside Width 46 in, Minimum Outside Width 28 in, Flange Width 2 in, Free Area 1.3 sq ft, Beginning Point of Water Penetration 766 fpm, Maximum Air Velocity 3000 fpm, Blade Angle 45 Degrees