Louver Damper Adjustable 30H x 30W

33 In.H 33 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Flanged Outside Height 29 1/2 in Outside Width 29 1/2 in Rough Opening Height 30 in Rough Opening Width 30 in Louver Maximum Intake 2 738 cfm Maximum Exhaust 3 916 cfm Flange Width 1 1/2 in Free Area 2.4 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 000 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 28 1/2 in Inside Width 27 3/4 in Number of Blades 6