Inogen One Portable Oxygen Concentrators "Free FedEx Next Day Shipping"
Oxygen anytime anywhere with up to 13 hrs use per charge at 2 liters per min. with Inogen One G5. Inogen One portable oxygen concentrators are absolutely the most reliable with most oxygen output in its class. The Inogen One G4 only weighs 2.8 lbs with single battery which can be used during any outdoor activity or even playing tennis.