Styles 0110DOW, 0120DOW, 0110GOW and 0120GOW are "out of wall or ground" integral sleeve static curtain type fire dampers.  Design 0110GOW and 0120GOW are precisely suitable for supply or return ducts that terminate at a grille or sign-up. Design 0110DOW and 0120DOW are designed for by penetrations (ductwork linked to https://dampers-for-industrial-se34456.blogsuperapp.com/37515371/helping-the-others-realize-the-advantages-of-heavy-duty-stainless-steel-damper-manufacturers