I am a retired or semi retired contractor/architect. I also tinker with inventions and the DDS-500 was an exact idea ofmine incarnate. I saw the tv advertisement while visiting my wife @ the hospital for her surgery and I just had to get a DDS-500 to see if it would work as well on my back problems as I had thought. It did so to a 150%of desired product effort. I had to convince my insurance company to examine and approve of medical equipment durability- they did and I wear it now for 1 ½ years.