Low-cost tracker. A fitness wristband for roughly 20 Euros with OLED panel, heart-rate monitor, IP67 certification and a battery life of over 20 days? The Chinese manufacturer Xiaomi makes it possible. We tested Xiaomi's Mi Band 2, and report how it fares in everyday use.
http://www.notebookcheck.net/Xiaomi-Mi-Band-2-Smartband-Review.168722.0.html