Inogen One G5 oxygen concentrator. Double battery. Runs on batteries, house current and 12 volt through vehicle cigarette lighter. Is portable and rechargeable. Recharges while on house current and while plugged into cigarette lighter in vehicle. Have lots of additional supplies that go with it. Has carrying case. Works well. $1,400.00. New, fully equipped with accessories as this one is would cost more than $2,500.00.