Louver Damper Adjustable 48H x 48W

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