Products 0110DOW, 0120DOW, 0110GOW and 0120GOW are "outside of wall or flooring" integral sleeve static curtain kind fire dampers.  Model 0110GOW and 0120GOW are especially made for supply or return ducts that terminate at a grille or register. Model 0110DOW and 0120DOW are designed for via penetrations (ductwork connected to https://paxtonvmdrf.ourcodeblog.com/37161252/heavy-duty-stainless-steel-damper-manufacturers-an-overview