Use to transition between PelletVent Pro to existing chimney such as DuraTech, DuraPlus or DuraPlus HTC. Requires a DVL/DuraBlack Chimney Adapter to fasten into support box or wall thimble, for 6”, use adapter 6DVL-ADC or 6DVL-ADT, for 8”, use adapter 8DVL-ADC or 8DVL-ADT.