Louver Damper Adjustable 12H x 12W

15 In.H 15 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Flanged Outside Height 11 1/2 in Outside Width 11 1/2 in Rough Opening Height 12 in Rough Opening Width 12 in Louver Maximum Intake 266 cfm Maximum Exhaust 381 cfm Flange Width 1 1/2 in Free Area 0.2 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 000 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 10 1/2 in Inside Width 9 3/4 in Number of Blades 2