Product D0110DOW, D0120DOW, D0110GOW, D0120GOW are "from wall or ground" integral sleeve dynamic curtain variety fire dampers. Design D0110GOW and D0120GOW are designed for offer or return ducts that terminate at a grille or sign-up. Model D0110DOW and D0120DOW are created for by means of penetrations (ductwork linked to both sides) https://heavydutystainlesssteelda91122.techionblog.com/37149118/the-single-best-strategy-to-use-for-dampers-for-industrial-sector