DUALIS® PGI is a range of twin wall flue stainless steel (air gap) flue especially designed for Pellet stoves and boilers, gas fires all either conventionally flued or room sealed in a domestic house The range is available in several diameters and with various accessories for an efficient and aesthetic use. DUALIS® PGI can be used as a new flue system or it can be used to connect to existing chimneys and can also be used to line an existing chimney.