ALUDEC A21 ducts are flexible, strong laminate ducts for various purposes. The ducts consist of multiple layers of aluminium and polyester, with a high tensile carbon steel spiral helix enclosed between the layers. The duct can be attached to round and oval connection parts without any problems. The fire resistance of the ALUDEC A21 duct is according to current international standards. Due to its unique construction, the different layers of polyester and aluminium are overlapping each other completely.