I had before Medisiana Vifit Tracker not communicating activity tracker that needed to be connected via USB to transfer data. I lost it! There, it syncs live to pair the phone easily with the NFC, and the software is a true spy everyday life. I adore. The bad thing: Only compatible with android 4.4 (KitKat), the Sony Xperia SP was not therefore took charge by default! A peak. Thank you developers have released the Xperia updates with Anroid 4.4 aka KitKat allows me to fully use this tracker, reliable, tough, waterproof. Only small problem, why striated bracelet? Dirt them too please!