This is a heavy-duty PVC construction encapsulating a high tensile steel wire helix that ensures there is no separation from the duct material. The flex is a strong polyester-covered material that acts as a unique extra airtight and durable barrier. Supplied in standard 6-meter length, compressed to 0.6 mtsIndividually boxedEasy to connect to either round or oval ductingSeamless smooth interior surface ensures a low-pressureThe lamination of the layer of pvc into one single product gives extra strength durability and stability