Product D0110DOW, D0120DOW, D0110GOW, D0120GOW are "outside of wall or flooring" integral sleeve dynamic curtain style hearth dampers. Model D0110GOW and D0120GOW are made for offer or return ducts that terminate in a grille or register. Design D0110DOW and D0120DOW are created for by penetrations (ductwork linked to either side) where https://dampers-for-industrial-se23455.estate-blog.com/36005528/an-unbiased-view-of-dampers-for-industrial-sector