Portable Oxygen Concentrator Machine - 5 LitreOxygen concentrator provides oxygen to a patient in need at substantially higher concentrations than those of ambient air. Air has about 20% Oxygen and 78% Nitrogen. The Concentrator presses out the Nitrogen and provides air with a higher concentration of Oxygen about 93% to 95%. It is used as an alternative to tanks of compressed oxygen when there is low oxygen saturation while sleeping, shortness of breath (Dyspnea), Chronic Obstructive Pulmonary