@waterboy, you're lucky. On the day at the doctor's office when I was diagnosed with ILD and was told I needed Oxygen, I asked the nurse for some names of places to call. She told me who they usually use, and I was upset, so I said fine. I'll use them. She didn't mention that I was also agreeing to use ONLY them for 5 YEARS as part of their contract. Consequently, Medicare pays for the rental on the huge unit I have at home, and any tanks I wish to order, but WILL NOT pay for a concentrator from another company until t he 5 years has expired. So I bought my concentrator out-right.