Versions 0110DOW, 0120DOW, 0110GOW and 0120GOW are "away from wall or ground" integral sleeve static curtain sort hearth dampers.  Product 0110GOW and 0120GOW are specifically made for source or return ducts that terminate at a grille or register. Design 0110DOW and 0120DOW are created for through penetrations (ductwork connected to https://dampers-for-industrial-se57899.blogripley.com/37740068/details-fiction-and-dampers-for-industrial-sector