Excellent condition, very handy portable unit, easy to use and maintain. High quality. Purchased new from Oxygen Plus in December 2022 for $5475 for my elderly mother in rest home. It was wonderful to use when taking her out, easy to attach to wheelchair, very light, and not too noisey, very discreet. It has an internal battery which lasts 3 hours, plus this unit can be run on normal 3-pin plug power, or 12 volt in car. A great versatile unit, able to provide independence and mobility Please refer to the Inogen One G5 website or Oxygen Plus website for more detailed information