I have a nice portable Oxygen Concentrator., It is an older model but works well.. It is a pulse type, meaning it provides oxygen when you take a breath. That is typical for most portable concentrators, however I needed one that provides continueous oxygen so i had to buy a new one. My Lose your gain as these are quite expensive.. I also have six batteries, a couple don't hold charge but I believe 4 do. I have the car adapter plug and the regular house plug also.. It comes with carrying case. Including the batteries this is over a $2000 value.