The FreeStyle Portable Oxgyen Concentrator from Airsep is among the smallest of the 22 FAA approved concentrators currently available. Weighing 4.4 lbs, the FreeStyle is an “easy to travel with” solution to getting where you need to go while using oxygen. The unit sits in an inconspicuous carry bag that looks more like a camera bag than a piece of oxygen equipment. The FreeStyle offers pulse delivery oxygen settings of 1-3. The unit itself has an internal battery, at a setting of 2 the battery will last 2.5 hours. To extend your range, a battery belt that you wear around your waist is available. With the battery belt at a setting of 2, you can get up to 6 hours of battery time.