... gastritis, upper respiratory tract infammation, bronchial asthma,atrophic rhinitis, stomatitis* Portable, easy to carry. Adaptation range *Trains, airplanes, ships, cars ... with asthma and pregnant women. Instructions and precautions *When machine is in use, do not touch the inner metal part ... the life of the machine.*Turn the power of the machine off when not in use. Portable Negative ion Air Purifier( ...