Main technical parametersResolution: 250×122Voltage: 3VPower supply: CR2450×2 button battery, standby time 250 daysScreen size: 2.1 inchesScreen type: E-ink electronic ink screenDisplay color: 3 colors of red, white and blackSize: 73×41mmShell color: white/blackCommunication method: BluetoothBluetooth version: Bluetooth 5.0Support operating system: Android