I don't know why I haven't blogged on this before as I've owned it for over 14 years; maybe because I only started blogging here in 2014. For a little over $100, this is my second best way, after my chiropractor, to get relief when my back gets out of wack. I just hang upside-down (at a steep angle, but not totally vertical) for 5 to 10 minutes and let the vertebrae stretch out. It does take a while to get used to having the extra blood rush down to the head, but that does fade.
They don't sell the model I bought anymore, but the one at this link is similar.