Versions 0110DOW, 0120DOW, 0110GOW and 0120GOW are "away from wall or ground" integral sleeve static curtain type fireplace dampers.  Model 0110GOW and 0120GOW are exclusively designed for provide or return ducts that terminate at a grille or register. Design 0110DOW and 0120DOW are suitable for by way of penetrations (ductwork https://heavy-duty-stainless-stee35678.theobloggers.com/43296556/details-fiction-and-dampers-for-industrial-sector