This is the one that I have. Price $22.00
This is a newer version of the above. Price $21.48
A better view of the above.
Another view. I do not have mine arranged this way.
A hang on the wall unit. CozyHoze
Another view of the CozyHoze $20.00
This one looks interesting. I would like to try it. $66.00
Here is a video. Quite impressive.
This article talks about sleep apnea and chronic hypoxia.