Add our name to the list of totally dissatisfied customers who do not NOT recommend Oxygentogo. From the first day when the nurse at my mother in law's rehab recommended them, AND said she would handle everything, it was a nightmare. I ended up have to scan and email paperwork directly to Oxygentogo. And then the hastle of being clear on when we needed the oxygen delivered to the rehab unit in Denton, TX...culminating when my mother in law went to her new physician here in Mississippi who turned off the machine. Battery went dead, and I could find no instructions. Called Oxygentogo in Wyoming...closed, of course early afternoon and got their answering service. By the time someone called me back I had already gotten on to the internet, found the manufacturer and downloaded and printed out the manual for the unit and figured out. How simply and stress free it would have been for Oxygen to have had someone on immediate call to help with problems. Never will I recommend Oxygentogo. My mother in law could have died by the time someone from the company called me back.