The smallest of the Oxyhealth line is the Solace 210 in the best way to describe it is the mini version of the Oxyhealth Vitaeris 320 which is the most main stream chamber found in doctor's offices. The Solace 210 is 22 inches in rated diameter and is great for someone that wants to lie in the chamber and not necessary do EWOT while in there.
Most people especially if it is their first chamber can't spend the price it costs for the Vitaeris 320 which usually is found in doctors's offices and those that want the largest chamber by them.
The Oxyhealth Solace 210 also goes to 1.3 ATA pressure like the other chambers of theirs except the Oxyhealth Quamvis 320 which goes to 1.4 ATA. The 1.4 version has belts and buckles.
The compressor that comes with the Oxyhealth Solace 210 also is an oilless compressor just like the larger models of theirs but is smaller since it is powered a smaller chamber. The filters are also in their compressor.
I strongly recommend trying out the different sizes of the Oxyhealth chambers to see which size you like best. If you type in hyperbaric chambers on Google.com you will probably find many places that will let you have a session in their chamber. Some even give free first time customers a free session. I know of some places that have first session is free advertisements. That is how I first had my session in the Oxyhealth Vitaeris 320 chamber.