sandanbob
Contributor
NAUI (naui.org) I believe is non-profit. They also offer free access to some of their e-learning courses, though no certification is granted. Last week, I worked through their nitrox e-learning as a refresher, just for fun. A note on the RAID manuals. They are available, as indicated, but there seems to be an expiration, so I would suggest you 'sign up' for them as you have time to work through. Also, I believe that their manuals (at least some of them) were translated into English, so not everything came through perfectly.