Features: Big Screen with Simple Operation: 3cm diameter Round display, 240*240pix, simple operating system. Perfect view angles, easy control KEY, quick in reaction with high sensitivity. BT Hand free calls, Phone Book text Push: BT hands-free call when you drive, call history, phonebook sync; local SMS; text other messages push; MP3 for local playback Heart-rate, Health Track, Alerts and Notification: Vibrating alert; Pedometer exercise step counting, the movement distance record; Sedentary long seat to remind; Sleep monitoring to detect the quality of sleep Wide Compatibility: For iPhone 6 6S 6 Plus 6S Plus 7 Plus Samsung S6 S7 S8; BT 4.0, APP for Android/IOS Long Time Endurance: 380mAh, low energy consumption, full charge for 2-3 days standby(depend on the actual using situation).