In short, this neat little device has improved my sleep significantly. OK, so sleep is complex, fickle and difficult to be objective about, but never the less, I have seen improvement. I have kept pretty good sleep hygiene for a while. You know, exercise, black out blinds, no screens or coffee before bedtime etc. But I also have sleep apnoea and use a CPAP machine. But I was going through a patch of very poor sleep that I could not resolve so when I heard of the Pebble I thought I'd give it a go. I was suspicious of claims (having laughed a magnets as a sleep aid) and the cost seemed high. But then what price would I put on functioning well during the day. I chatted to Anna and felt there were some reasonable claims being made, even allowing for the placebo effect (and that's not a bad thing if it gives desired results). I decide to try a small dose of magnesium as well as Anna recommended that as important. I also rearranged the room to keep away from the Wifi router and other EM sources. Initially the results were not definite. Then I realised that the power adapter for my radio was under the bed, directly below my head. No doubt radiating like crazy. So, I started turning it off when going to sleep and the results became much better defined. I now find I sleep well and even if I do wake up a few times, I very quickly go back to sleep. I wake up feeling refreshed. And I'm much more active and able to perform my work (software developer). I'm also enjoying my music practice again. I get best result with both the Zee and magnesium. So on balance, this little device does work for me. I have an electrical / electronic engineering background so have a healthy scepticism. but I also realise that we know little about the physiological impact of electromatic radiation. The very low powers produced by the Zeez may seem insignificant but my experience is positive. I'm reasonably confident there is a scientific knowledge gap here. Finally a few words on the device itself. I have the black pebble which is a pleasing size and shape. There's just and on/off switch with an integral power light and a charger socket. There's been a manufacturing teething problem resulting in the button being a rather hard to activate with almost no tacktile feedback. But it works. It is also not easy to turn off, a good thing, requiring two presses. I find the battery only lasts two nights but then it's easy to pop on charge. Speaking of which, the supplied lead works fine but it does not charge with my laptop rapid charge supply and lead - again not a real problem, just odd. So in conclusion this is highly recommended. You might find it a winner if you have problems sleeping, have tried everything (or not) and are willing to make a few changes to your room to reduce EM interference, you might be like me and become a happy customer.