42 In.H 45 In.W Drnbl Extrd Alu Combo Dmpr Louver Type Combination Frame Type Hat Channel Outside Height 47 1/2 in Outside Width 47 1/2 in Rough Opening Height 48 in Rough Opening Width 48 in Louver Maximum Intake 5 027 cfm Maximum Exhaust 7 219 cfm Flange Width Not Applicable Free Area 7.2 sq ft Beginning Point of Water Penetration 1 118 fpm Maximum Air Velocity 3 000 fpm Blade Angle 45 Degrees Material Aluminum Inside Height 46 1/2 in Inside Width 45 3/4 in