Which is the smallest home medical grade oxygen concentrator (oxygen machine) (oxygen absorber)?

The smallest oxygen concentrator is Foshan's Kaiya Oxygen Concentrator: tailor-made by the most authoritative compressor supplier in China, it is the smallest three-liter oxygen concentrator in the country, weighing only 9kg, easy to carry, and occupies an absolute leading position among similar products. Low energy consumption, less than 180W per hour, less than 10 cents per hour power consumption, is the most economical choice of oxygen therapy, and its performance is by no means lost with the same category of large models; with the volume and low energy consumption as its biggest advantage in the oxygen machine ranking third.