Working temperature: 0~40'C; Compatibility: Android: 4.3 and above, WeChat 6.0 and above, bluetooth 4.0; IOS: 7.0 and above, WeChat 6.0 and above, IPHONE4S/5/5C/5S/6/6PLUS; Features: when start up, it will in turn display time, date, steps and calories.