•SONOAFS-ALU thermally and acoustically insulated aluminium flexible air ducts are specifically produced for low and medium pressure heating, cooling, ventilation, exhaust, and air conditioning systems. •Airtight SONOAFS-ALU is produced from multi layer aluminium and polyester (perforated), strengthened with high tension hard steel spring wire, surrounded with glass wool insulation and an aluminium vapour barrier. •SONOAFS-ALU has high elasticity and flexibility. It can be easily fitted to circular, oval, or rectangular connectors. •The fire resistance of SONOAFS-ALU has been tested and certified by various international bodies.