DuraFlex AL 3 in. Dia Coupling

Dura Flex Aluminum is for use as air intake only. Aluminum Flex liner available in 25 ft., 35 ft. and 50 ft. flex lengths. Constructed of single-wall (1-ply) aluminum.|Flexible aluminum relining for masonry chimney|Use with natural gas or liquid propane category 1, draft hood equipped appliances and appliances tested and listed to use type B gas vent|Applications include natural gas fireplaces, gas-fired furnaces, boilers, water heaters and wall or space heating appliances|0 in. clearance to masonry|Available in 3 in thru 8 in.|Limited lifetime warranty|Listed to UL 1777 and ULC S645