The Inogen One G4 portable oxygen concentrator is remarkably quiet, with a noise level of up to 40 decibels or the equivalent of a quiet library. It has up to level three oxygen flow settings, and ideal for those who do not need more than level four settings. Since it is compact, you can use it at home and bring it with you at work or for leisure. It is very energy efficient and uses less electricity than most models, so you save money. You can use it at home and bring it to your office or on travel so you can have supplementary oxygen when needed. The Inogen One G4 Pulse Portable Oxygen Concentrator is a better alternative to oxygen tanks, and gives you better capability to do more things and be more independent. This device delivers adequate flow of oxygen and rated for everyday use. It uses little power and is clinically validated to deliver adequate oxygen during all phases of daily activity and sleep.