The DuraVent 6DF304-30 DuraFlex 304 stainless steel length is a flexible relining for your masonry chimney. It is designed to be used with gas, oil, wood pellet or wood appliance. This has an inner diameter of 6 inches and a length of 30 feet. Search only for the best and high-quality products for your vent and chimney system. In cooperation with DuraVent, PlumbersStock.com has everything you need at affordable prices. Go find yours now here at PlumbersStock.com!