44.75 In.H-W Alu Universal Backdraft Dampr Frame Material Aluminum Number of Panels 1 Maximum Air Velocity 2250 fpm Overall Height 44 3/4 in Rough Opening Shape Square Fits Fan Diameter 42 in Free Area 9.7 sq ft Overall Width 44 3/4 in Frame Material Thickness 0.1 ga Frame Depth 1 5/8 in Rough Opening Length 43 in Maximum Pressure 1 in wc Rough Opening Width 43 in Blade Material Aluminum Single Acting/Double Acting Single Acting Closure Type Spring Flange Width 1 3/8 in