Philips EverFlo Oxygen Concentrator, Made in USA America A medical device for home use designed to provide a continuous source of oxygen for patients who need oxygen therapy. Function: The device draws in room air, filters it, separates oxygen from nitrogen, and delivers concentrated oxygen at a high percentage (up to 90-96%) to the patient. Features: The device features a compact and relatively lightweight design (about 14 kg), making it easy to move around the house, and it operates at a low noise level. The device is almost new