... . Acoustic insulated duct made of aluminum foil + pet + helix steel wire + fiber glass2. Apply for low/medium/ high pressure, use for ... , laboratory, howff, bus, train, broadcasting studio.Specifications:Structure: High elastic wire, aluminum foilStandard Diameter: 3, 4, 5, 6, 8, 10, 12 ... range: -30 degree to + 200degreeAir Velocity: 28m/sWorking Pressure: 250mmAq air conditioning non-insulated duct