This UL non-insulated aluminum flexible air connector is specifically produced for low and medium-pressure heating, cooling, ventilation, exhaust, and air conditioning systems. It is produced from multi-layer aluminum and polyester, strengthened with high-tension hard steel spring wire. It has high elasticity and flexibility. It can be easily fitted to circular, oval, or rectangular connectors. The fire resistance has been tested and certified by various international bodies. In the event of a fire, no toxic or poisonous gases are released. The dimensions, tolerances, and mechanical resistance were tested, classified, and certified according to EN 13180.