Respircare oxygen concentrator contains two OC machines a 3-liter machine (AO3W/AO3) and a 5-liter machine (AO5W/AO5). Oxygen is produced by molecular sieves, can give 1-5L/min oxygen stream with oxygen fixation ≥93%. It has little volume, low clamor, and long assistance life advantage is appropriate for oxygen treatment of homecare with 1 Year Warranty.