DuraFlex AL 4 in. Dia x 420 in. Flex Length

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 S655