I use an inogen backpack machine, it comes with two batteries one rated for eight hours and the backup is rated for five hours. Comes with a vehicle charge cord and a 110 for charging in the house. I'm in a wheelchair and this thing fits on the back of the chair. It made going places100% easier. I paid $1900 for mine have had it for almost two years had to replace the filters once. Very easy to do.I would be lost without it.
