Model D0110DOW, D0120DOW, D0110GOW, D0120GOW are "away from wall or floor" integral sleeve dynamic curtain type hearth dampers. Product D0110GOW and D0120GOW are created for supply or return ducts that terminate in a grille or sign up. Design D0110DOW and D0120DOW are suitable for by penetrations (ductwork connected to either side) https://tysonmdtiv.blogsvirals.com/36018200/the-5-second-trick-for-dampers-for-industrial-sector