Great machines for certain types of pain in certain areas - I found it wonderful when I first had my lower back pain in my early 30s (pre-fibro days) from a severe fall, as I could put the pads either side and often left it on all day long with great relief. However, I've found it much harder to use for neck, shoulder or arm pain, as I find now I can't get the pads placed where they're not just making the muscles twitch strongly rather than just pulsate between them. So it very much depends on where you want to use it, and whether you've patience for trying to place the pads constantly for best effect, but if you can, and if you take it slowly, then I think they're a superb device and I truly wish I could use mine more.