Oxygen therapy can be given for a short or long period of time in the hospital, another medical setting, or at home. Oxygen is stored as a gas or liquid in special tanks. These tanks can be delivered to your home and contain a certain amount of oxygen that will require refills. Another device for use at home is an oxygen concentrator, which pulls oxygen out of the air for immediate use. Because oxygen concentrators do not require refills, they won’t run out of oxygen. Portable tanks and oxygen concentrators may make it easier for you to move around while using your therapy.