Louver Damper Adjustable 24H x 30W

26.5 In.H 32.5 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Flanged Outside Height 23 1/2 in Outside Width 29 1/2 in Rough Opening Height 24 in Rough Opening Width 30 in Louver Maximum Intake 2 136 cfm Maximum Exhaust 3 054 cfm Flange Width 1 1/2 in Free Area 1.9 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 27 3/4 in Number of Blades 4