Product D0110DOW, D0120DOW, D0110GOW, D0120GOW are "from wall or floor" integral sleeve dynamic curtain variety hearth dampers. Design D0110GOW and D0120GOW are created for supply or return ducts that terminate at a grille or sign-up. Design D0110DOW and D0120DOW are designed for by means of penetrations (ductwork connected to each side) https://heavy-duty-stainless-stee35677.worldblogged.com/43076378/the-basic-principles-of-dampers-for-industrial-sector