The DuraVent 3DFA-25 is an aluminum length from the DuraFlex AL, an economical venting system that is designed to reline and protect the masonry chimney from damages due to flue product condensation. It is used with natural gas, appliances tested and listed to use Type B gas vents, and draft hood equipped appliances. It has an inner diameter of 3 inches and a length of 25 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!