Louver Damper Adjustable 24H x 24W

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