... as tunnel, basement, ship building or welding, laboratory ,air-conditioner. flexible duct:/air duct/exhaust duct,ventilating duct,flex duct1,Material ... 10m4,Main color: yellow,red,orange .white,black,green ect.5,Character: enduring high temparature,acid,alkali,oleic acid, harmful liquid ... ventilator to use together. good quality portable ventilator with pvc flexible duct for industry project