DuraFlex SS Stainless Steel Chimney Liner - 4" x 20-ft. - 4DF316-20: A 4" inner diameter vent pipe is required for this unit. The stainless-steel chimney liner from DuraFlex is ideal for straight chimneys. When used with heating appliances and fireplaces, this liner protects brick chimneys from the substance that threatens to corrode them. The liner is compatible with wood pellet, non-condensing gas coal, and oil appliances. It measures 4" around and 25-feet long. It isn't particularly heavy, so the liner should be simple to install. This liner comes with a limited lifetime warranty from the manufacturer.

DuraFlex 25 Stainless Steel Chimney Liner 4-in. diameter Light-weight .006" metal thickness makes it stronger than other light liners Most economical liner for straight chimneys Manufacturers limited lifetime warranty