32 In.H-W Aluminum Spring Backdraft Damper Frame Material Aluminum Number of Panels 1 Maximum Air Velocity 2000 fpm Overall Height 32 in Rough Opening Shape Square Fits Fan Diameter 30 in Free Area 5.3 sq ft Overall Width 32 in Frame Material Thickness 0.1 ga Frame Depth 1 5/8 in Rough Opening Length 30 in Maximum Pressure 1 in wc Rough Opening Width 30 in Blade Material Aluminum Single Acting/Double Acting Single Acting Closure Type Spring Flange Width 1 3/8 in