The concentrator filters the oxygen from the air. The compressor absorbs the air and drives it to different purifying filters. Later on, three molecular sieves grant the separation from the oxygen and the nitrogen. It works in an alternative way, granting a quick increase in the oxygen concentration, with a constant flow, at the same time as the device is switched on. A long life tester, measures in all times the oxygen concentration the device gives. Low oxigen concentration alarm.