Dayton Louver Damper,Adjustable,48H x 48W 20UA30

51 In.H 51 In.W Drnbl Extrd Alu Combo Dmpr, Louver Type Combination, Frame Type Flanged, 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 8,014 cfm, Maximum Exhaust 11,460 cfm, Flange Width 1 1/2 in, Free Area 7.2 sq ft, Beginning Point of Water Penetration 1,118 fpm, Maximum Air Velocity 3000 fpm, Blade Angle 45 Degrees , Material Aluminum, Inside Height 46 1/2 in, Inside Width 45 3/4 in, Number of Blades 10