The MFD-36 Round Control Damper is ideal for controlling air flows in Commercial, Institutional and Process air systems. Dampers are constructed with an 18GA Galvanized steel frame and a double steel blade with an internal neoprene seal. Corrosion resistant zinc plated 1/2" diameter shafts with a 6" extension, on one side, for connecting an operator and oil impregnated bronze bushings. Dampers are undersized by 1/8".  Available options include manual hand quadrant operators, 24 Vac & 120 Vac electric operators.