Product details:

The DuraVent 6DFA-25K AL Kit is suitable for relining your masonry chimney as it protects your masonry chimney from the damaging effects that is caby flue product condensation. This can be on natural gas fireplaces, gas-fired furnaces, water heaters, boilers, and wall or space heating applications. Included in the kit are a DuraFlex AL length, a DuraFlex top plate, a DuraFlex AL cap, and a DuraFlex Mortar Sleeve. It measures 6 inches in diameter and the flex has a length of 25 feet.