The Inogen One G2 Portable Oxygen Concentrator has earned the distinction of being the lowest-priced, major brand portable oxygen concentrator. This economy allows the Inogen One G2 to provide greater independence to more oxygen patients. Inogen One Concentrators are clinically proven to provide the necessary oxygen for most ambulatory patients during all phases of daily activity and sleep. Compared with other major selling Portable Oxygen Concentrators, the Inogen One G2 Concentrator has one of the lightest weights on the market — even beating the Invacare XPO2 by .05 pounds. In comparing sizes, the G2 is the second smallest oxygen machine. Comparing sound emissions, the G2 emits the lowest decibels at only 38. The AC power supply is auto sensing to allow worldwide use. The G2 Oxygen Concentrator is authorized by the FAA for commercial airline travel, making the G2 truly Oxygen Concentrator.