Smoke dampers are passive fire protection products used in air conditioning and ventilation duct work or installed in physical smoke barriers (e.g., walls).  This may be done to prevent the spread of smoke from the space of fire origin to other spaces in the same building.  Made of Galvanized Iron or Stainless Steel.  Available in single blade or multi-blade system, square or round versions.  Can be with flanged type or non-flanged type.