Combo Louver Damper Adj 23-1/2 H Alum

18 In.H 21 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Hat Channel Outside Height 23 1/2 in Outside Width 23 1/2 in Rough Opening Height 24 in Rough Opening Width 24 in Louver Maximum Intake 1 005 cfm Maximum Exhaust 1 444 cfm Flange Width Not Applicable Free Area 1.3 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 000 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 22 1/2 in Inside Width 21 3/4 in Number of Blades 4