Nine layers of world-class circuit chip protection � Temperature Resistance � Protection from Short Circuit � Reset Mechanism � Input Overvoltage Protection � Protection from Incorrect Insertion � Protection from Output Overcurrent � Output Overvoltage Protection � Protection from Overcharge and Over-discharge � PTC Protective Circuits for the Cell USB-C + Dual USB-A Output 3-USB output for simultaneous charging needs Double press for low power charging Safely charge low power devices such as Bluetooth headsets and fitness bands. Simply double press the power button to enter 2-hour low power charging mode. * Mi Power Bank 3 20000mAh also supports low power charging for other brands devices like Bluetooth headsets, fitness bands and other smart devices.