Product D0110DOW, D0120DOW, D0110GOW, D0120GOW are "outside of wall or flooring" integral sleeve dynamic curtain style hearth dampers. Model D0110GOW and D0120GOW are created for offer or return ducts that terminate at a grille or register. Product D0110DOW and D0120DOW are created for as a result of penetrations (ductwork linked to https://augustfwnbp.blue-blogs.com/44443451/rumored-buzz-on-heavy-duty-stainless-steel-damper-manufacturers