DuraVent DuraFlex AL 3" Aluminum Coupling startup-kit when the unit is very

when the unit is very hot

It is also know as rock wool

15" (W) x 8

Item Number AH2231P  Product Type Hood

Factory-installed blower included

DuraVent DuraFlex AL 3" Aluminum Coupling startup-kit when the unit is veryDuraFlex Aluminum An economical venting system used for relining masonry chimney for natural gas or liquid propane category I, draft hood equipped appliances, and appliances tested and listed to use Type B Gas Vent for a wide range of applications, including: natural gas fireplaces, gas fired furnaces, boilers, water heaters, and wall or space heating applications. Protects the masonry chimney from damaging effects of flue product condensation.