DuraFlex SS Stainless Steel Chimney Liner - 6" x 20-ft. - 6DF316-20: A 6" inner diameter vent pipe is required for this unit. DuraFlex's stainless-steel chimney liner has a thin metal thickness of .006", making it stronger and more durable than conventional chimney pipe liners, while remaining lighter. This chimney liner has a diameter of 6" and a length of 20 feet. It is made of 304 and 316Ti stainless steel and is UL Listed to the UL1777 standard. DuraFlex SS flexible masonry chimney relining pipe is designed for use with gas, wood pellet, oil, or wood appliances such as furnaces, boilers, fireplace inserts, and water heaters.

DuraFlex 20 Stainless Steel Chimney Liner 6-in. diameter Light-weight .006" metal thickness makes it stronger than other light liners Most economical liner for straight chimneys Manufacturers limited lifetime warranty