Louver Damper Adjustable 60H x 18W

62.5 In.H 20.5 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Flanged Outside Height 23 1/2 in Outside Width 17 1/2 in Rough Opening Height 24 in Rough Opening Width 18 in Louver Maximum Intake 3 414 cfm Maximum Exhaust 4 882 cfm Flange Width 1 1/2 in Free Area 3.1 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 000 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 58 1/2 in Inside Width 15 3/4 in Number of Blades 12