Product D0110DOW, D0120DOW, D0110GOW, D0120GOW are "from wall or floor" integral sleeve dynamic curtain form hearth dampers. Design D0110GOW and D0120GOW are created for source or return ducts that terminate at a grille or sign up. Model D0110DOW and D0120DOW are suitable for via penetrations (ductwork linked to both sides) in https://heavy-duty-stainless-stee24566.tinyblogging.com/considerations-to-know-about-heavy-duty-stainless-steel-damper-manufacturers-80684423