They are very effective devices for back pain, my therapist recommended them to me and I use them to keep my back in good health, but their website gives a lot of information.
Very nice stuff, but shipping takes too long to arrive. Customer service is just as time consuming. The costs are not that bad but they are pretty average.
They have the worst customer service you have ever experienced. In general your chain is good. But the customer service is from the but, especially since it is foreign