Thermally insulated aluminium flexible air ducts are specifically produced for low and medium pressure heating, cooling, ventilation, exhaust, and air-conditioning systems. Hose is produced from multi-layer aluminium and polyester, strengthened with high-tension hard steel spring wire, surrounded with glass wool insulation, and protected by an aluminium vapour barrier. The hose has high elasticity and flexibility, allowing it to be easily fitted to circular, oval, or rectangular connectors. The fire performance of the hose has been tested and certified by various international bodies.