Louver Damper Adjustable 48H x 36W

51 In.H 39 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Flanged Outside Height 47 1/2 in Outside Width 35 1/2 in Rough Opening Height 48 in Rough Opening Width 36 in Louver Maximum Intake 5 877 cfm Maximum Exhaust 8 404 cfm Flange Width 1 1/2 in Free Area 5.3 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 000 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 46 1/2 in Inside Width 33 3/4 in Number of Blades 10