An Oxygen Concentrator is a Class II medical device that delivers 90-95% pure supplemental oxygen to patients with chronic hypoxemia using pressure swing adsorption (PSA) technology to concentrate oxygen from room air. Available as stationary/home units (10-30 kg, 0.5-10 L/min continuous flow) for long-term oxygen therapy (LTOT) and portable/ambulatory units (1-10 kg, 0.5-3 L/min pulse-dose or continuous flow) for active patients requiring mobility. Features include oxygen purity monitoring with alarms, digital flow control, hour meters, washable filters, and (for portable units) rechargeable batteries, FAA approval for travel, and pulse-dose delivery to conserve oxygen. Primary clinical indications include COPD, pulmonary fibrosis, cystic fibrosis, and other chronic respiratory conditions with resting, exertional, or nocturnal hypoxemia (PaO2 ≤55 mmHg or SpO2 ≤88%). Essential for home-based oxygen therapy, enabling patients to maintain independence, reduce hospitalizations, and improve quality of life. Critical safety precautions include NO SMOKING in the oxygen environment, keeping away from heat sources and open flames, proper electrical safety, regular filter cleaning, and having backup oxygen for power outages.