Model D0110DOW, D0120DOW, D0110GOW, D0120GOW are "outside of wall or floor" integral sleeve dynamic curtain type hearth dampers. Model D0110GOW and D0120GOW are made for supply or return ducts that terminate in a grille or sign up. Design D0110DOW and D0120DOW are designed for as a result of penetrations (ductwork linked https://heavydutystainlesssteelda90011.blogolize.com/the-best-side-of-dampers-for-industrial-sector-75851679