Use this part to adapt your Pellet vent Pro chimney to a 6-Inch "Simpson DuraTech or DuraPlus" class "A" HT chimney system. You must use a "Duravent DVL 6in Duratech Adaptor" adaptor between this product and the Simpson ceiling support or finishing collar (found on the DuraTech & DuraPlus Chimney Pipe pages). This may fit other chimneys with a single wall male end down but fittment is not guaranteed.