There are a wide variety of oxygen concentrators. Portable models are also available that vary based on size, intended use, and the type of oxygen therapy your doctor has prescribed. Oxygen concentrator portable units extract and release nitrogen from the air resulting in a higher concentration of pure oxygen, which is variable depending on the prescribed dosage. Oxygen concentrators are safer, less expensive and more convenient alternatives to oxygen tanks. We carry both home oxygen concentrators and portable units. Pulse dose delivery and continuous flow delivery systems are available in certain models. Our customer service agents are available to help you select the o2 concentrator portable model that's right for you. Please contact us with any questions.