Combination Louver Damper 12x12

12 In.H 12 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Hat Channel 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 131 cfm Maximum Exhaust 206 cfm Flange Width Not Applicable Free Area 0.3 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 500 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 10 1/2 in Inside Width 9 3/4 in Number of Blades 2