After much research on Amazon and Google I decided for this device and even though I knew that the device is not waterproof. Me have the "automatic stairs count" and the "automatic sleep monitoring" convinced to buy. Unfortunately, there is precisely because of these 2 properties a point deduction. I get so around the 10-12 floors per day and go after work to the station. The normal climbing stairs will be rewarded with 4 floors usually with 5-6 storeys. Since the station is located on a mountain, he shows me to Erreichchung the station 35 or 37 floors to, that is not true and is not at all. The automatic "sleep mode" unfortunately does not so readily. While I was sitting about 1 hr. On PC and diligently "gklimpert" on the keyboard have, the unit said, I "slept" when reading it is like that ... Now I like my old pedometer. At this device I have to manually set the "sleep mode" and then also works perfectly (1 point deduction). I have a Armumpfang of 165 mm. According to size specification of the Fitbit wristband is 157-193mm long and in size S 137-157mm long for size L. My Armumpfang is 165mm and after the application of the bracelet still 2 Verschlüssösen were free. Unfortunately, the bracelet for my thin arms is not suitable because construction technology requires the bracelet on both sides is not applied and as always disturbing the "way" was. Because the bracelet is not abutted right, it always bothered, whether at night or during the day. So I have the band after 2 days again need to send back (the 2nd point deduction). Conclusion: The instrument itself has already fallen to me, but more detailed information I ask already. The operating instructions you should invite unbedigt from the Internet, as it is much good stuff in there to handle. Now I'm going to fuse the million look again and see if the strap rests on my arm. This bracelet would even waterproof ...