... 3,Oil, Acid, Alkai & high temperature Resistantflexible duct:/air duct/exhaust duct,ventilating duct,flex duct, ventilation duct 1,Material: PVC flam-resistant static-free fabric ... ,Oil, Acid, Alkai & high temperature Resistant flexible duct:/air duct/exhaust duct,ventilating duct,flex duct, ventilation duct 1,Material: PVC flam-resistant static-free fabric ...