Round 13.9 In.dia Motorized Smoke Damper For Nominal Duct Diameter 14 in Damper Application Smoke Number of Panels 1 Overall Height 13 7/8 in Overall Length 8 1/8 in Rough Opening Shape Round For Duct Shape Round Overall Width 8 1/4 in Frame Material Thickness 20 ga Blade Material Galvanized Steel Maximum Air Pressure 4 in wg Overall Diameter 13 7/8 in Rough Opening Width 14 in Damper Type Dynamic Maximum Air Velocity 3000 fpm Nameplate Voltage 24V DC