Recommended reason24 hours PER sec sustained heart rate monitoring--UPGRADED fitness tracker can support 24 hours per second to monitor your heart rate, different from the past monitoring per hour; Monitoring your heart rate to help you do exercise scientifically and help you get a better understanding of your fitness levelSleep monitor--Synchronize your sleep time every night and analyze your sleep quality by the sleep trend graphs; Accurately monitor total effective sleeping time and motions every night, you can better understand your sleeping quality.Multi functions --Pedometer, Calories, Distance, Heart Rate Monitor, Blood Pressure ,Blood Oxygen,Sleep quality measurement, Call reminder, Alarm clock,Stopwatch,Search bracelet and so on, these amazing features are available, do not hesitate; App is more comprehensive, now it is updated version. Besides, it is with high quality comfortable and fashion strap.Wide compatibility & Long-lasting battery--Full charge requires only 1-2 hours and the standby time can be up to 3 days with full power. App supports most smart phones with Bluetooth 4.0 or above. Support system: iOS 8.5 or above.Android 4.4 or above .In addition to the iPhone5 seriesReminder many APP message , Wecht /QQ/Microblogging/facebook/twitter/whatsapp/line/kakaotalk (open you APP , click mine -click Device management-click intelligent reminder -click APP reminder -- setting what you want (Wecht /QQ/facebook/twitter/whatsapp) Instructions for the first user : 1.When using this equipment for the first time, The smart bracelet battery has no power ,please take out the device , charger it first2.the charging clip caught on the host of the smart bracelet during the charging ,the palping foot on the charging lip align to the palping foot on the main body .3.2.the screen will have light and in clock screen when touch button be clicked . single click can switch different pages .the screen will out of light when no action happened after 6 seconds.4). Be compatible with Android ( Android 4.4 or above ); for iPhone ( iOS 8.5 or above )