I am on oxygen 24/7. I have been called for Jury Duty. The Sequel unit for my home use is also the only unit I have for travel use and I plug it into a charge in the car while out and about. When not on charge, it lasts about .45 minutes on it's own battery before it begins to scream (loudly). This unit would never sustain me in a jury setting. (BTW, I am still researching the smaller portable units and looking at cost, etc.) I would like to know what others do in this situation. Thank you!