Now I use the small device since 4 weeks and am thrilled. I was interested to increase my physical activity in the first place. Since I spend a lot of time on a PC and want to know how much / how little I move, I bought this unit because I get the evaluation via the PC and the graphs clearly show my results. In addition, I also get information about how well I sleep. Sometimes I had the feeling I had as good as not slept, or how to says- so I could not sleep a wink! If I the device adjusting evening at bedtime, I can read the next day, as I slept, ie whether and how long were my deep sleep, how many times I moved a little or more often. This, I learn that there is no reason to complain, because according to diagram I sleep every night in between very soundly. And my feeling, I could not sleep a wink, is refuted !!! Since then, I feel better and can also sleep well, because now I know that I have only imagined the lack of sleep and feel based on very subjective sensation.