Dayton Louver Damper,Adjustable,24H x 24W 20UA22

27 In.H 27 In.W Drnbl Extrd Alu Combo Dmpr, Louver Type Combination, Frame Type Flanged, Outside Height 23 1/2 in, Outside Width 23 1/2 in, Rough Opening Height 24 in, Rough Opening Width 24 in, Louver Maximum Intake 1,661 cfm, Maximum Exhaust 2,375 cfm, Flange Width 1 1/2 in, Free Area 1.5 sq ft, Beginning Point of Water Penetration 1,118 fpm, Maximum Air Velocity 3,000 fpm, Blade Angle 45 Degrees , Material Aluminum, Inside Height 22 1/2 in, Inside Width 21 3/4 in, Number of Blades 4