... 1.type:insulated pu duct 2.air duct panel size:3.9mx1.2m 3.ISO9001/14001 4. ... easy to make ,install PU ventilation air duct PU air duct panel suitable material for making air conditioning ducts,wildly used in market ... /m.k. It’s widely used for ventilation systems of central air conditioning units in hotels, apartments ,hospitals, office buildings and other ...