Hyperbaric Chambers: https://www.oxyhealth.com/
There are others, some less expensive. BUT, this is the best. I looked on youtube and found that you can build one for less than a couple of hundred dollars. Check that out too.
This is a problem, because I am using 1-part THC to 1-part CBD, which is illegal in half the country. I do know you need to get it from the cannabis plant, not the hemp plant.