15.75 In.H-W 5 In.L GStl Volume Control Dampr, Damper Application Volume Control, Frame Material Galvanized Steel, Number of Panels 1, Maximum Air Velocity 3000 fpm, Overall Height 15 3/4 in, Rough Opening Diameter Not Applicable, Rough Opening Shape Square, Fits Fan Diameter Not Applicable, For Duct Shape Square, Overall Width 15 3/4 in, Frame Material Thickness 16 ga, Overall Length 5 in, Connection Type Not Applicable, Frame Depth 5 in, Rough Opening Length Not Applicable