Military grade standard Outdoor smart watch has 10 military grade certifications and withstands harsh environmental conditions: 70 heat resistance, -40 cold resistance; 120 hours resistance to humidity, 96 hours resistance to salt spray. Multifunctional smart watch Activity trackers (pedometer, distance, calories), heart rate monitor, 10 sports modes, shared GPS, sleep monitoring, message notification (Call, SMS, Facebook, Twitter, ...), search cellphone, music control, stopwatch, countdown timer, Sedentary setup, alarm setup, photography, female monthly period management, 10 selected dial modes. Long-lasting battery 10 days of battery life with a typical use scenario, 30 days with a simple use scenario and 20 hours with Bluetooth phone calling continuously on, for iOS Android. Sleep & Heart Rate Monitor The smartwatch has a built-in optical sensor, which can not only monitor your heart rate and blood pressure in real time 24 hours a day, but also automatically track your quality of sleep. night (to help you understand and improve the quality of sleep). When you use this smartwatch, it can tell your health anytime, anywhere.Compatible with Android / iPhone This connected watch is compatible with Android and iOS phones. Download and install the free "DaFit" app by scanning the QR code in the manual or by searching the App Store. Compatible systems: iOS 8.0 or higher, Android 4.0 or higher. (not for iPad / PC devices). Turn on the phone's bluetooth and connect to the smart watch via APP.