23.75 inH 16 inL 24 inW GStl Fire/Smke Dampr For Nominal Duct Diameter Not Applicable Damper Application Fire and Smoke Number of Panels 1 Overall Height 23 3/4 in Overall Length 16 in Rough Opening Shape Square For Duct Shape Square Overall Width 24 in Frame Material Thickness 16 ga Blade Material Galvanized Steel Maximum Air Pressure 4 in wg Overall Diameter Not Applicable Rough Opening Width 24 in Damper Type Dynamic Maximum Air Velocity 2000 fpm Nameplate Voltage 120V AC