I have just recently been approved for supplemental O2 during the day when I exsert  myself. I have been sleeping with O2 at 2 lt continuous flow for about one year. Because I only want to take short 3-4 day trips, saying different palaces each night, I am considering purchasing a poc that I can both carry and sleep with at night. I have  looked on line and made several calls. Now I am more confused than ever. Currently I am looking at Activox and Inogen. Any suggestions/information would be greatly appreciated. My Dr doesn't seem to have an option. Thanks in advance.