Design D0110DOW, D0120DOW, D0110GOW, D0120GOW are "away from wall or flooring" integral sleeve dynamic curtain style fireplace dampers. Product D0110GOW and D0120GOW are designed for offer or return ducts that terminate in a grille or sign up. Model D0110DOW and D0120DOW are suitable for through penetrations (ductwork linked to each side) https://dampersforindustrialsecto35566.blogsidea.com/43560689/rumored-buzz-on-heavy-duty-stainless-steel-damper-manufacturers