Combo Louver Damper Adj 17-1/2 H Alum

12 In.H 15 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Hat Channel Outside Height 17 1/2 in Outside Width 17 1/2 in Rough Opening Height 18 in Rough Opening Width 18 in Louver Maximum Intake 438 cfm Maximum Exhaust 625 cfm Flange Width Not Applicable Free Area 0.5 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 000 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 18 in Inside Width 18 in Number of Blades 3