Model D0110DOW, D0120DOW, D0110GOW, D0120GOW are "away from wall or floor" integral sleeve dynamic curtain form hearth dampers. Product D0110GOW and D0120GOW are made for source or return ducts that terminate at a grille or sign up. Model D0110DOW and D0120DOW are created for via penetrations (ductwork linked to both sides) https://dampers-for-industrial-se23344.blog4youth.com/37504052/everything-about-heavy-duty-stainless-steel-damper-manufacturers