Specifications:Display Size: About 0.86 inches OLED ScreenBand Material: Soft TPUBluetooth: V4.0Memory : 32KB RAM+256KB ROMPower supply:DC 3.7V rechargeable batteryBattery Type: Lithium-ionCharging Interface:USB PortCharging Time:1-2 hoursStand By Time: 4-5 daysApplication system:iOS 7.1 & above, Android 4.4 & aboveFeatures: Heart rate monitor|Time|date|battery display|step pedometerCalorie|distance|auto sleep monitor|alarm alert|SMS alertCall alert|anti-lost|sedentary alert|camera remote shootFunctions:24 Hour continuous heart rate monitor.Call Alert: The tracker vibrates and the call is displayed on the screen when there is an incoming call.Sedentary Alert: Set reminders for periods of time of inactivity.SNS Alert: Receive notifications from other apps.SMS Alert: Read incoming text messages on your tracker screen.Find Phone: Set the tracker to locate your phone by making the phone vibrate or ring.