Styles 0110DOW, 0120DOW, 0110GOW and 0120GOW are "out of wall or flooring" integral sleeve static curtain form fire dampers.  Model 0110GOW and 0120GOW are specially designed for provide or return ducts that terminate in a grille or sign up. Model 0110DOW and 0120DOW are made for by penetrations (ductwork connected https://grease-tight-extract-duct90011.dailyblogzz.com/37609003/little-known-facts-about-heavy-duty-stainless-steel-damper-manufacturers