Mobile devices are always running out of juice at inconvenient times. A way of getting around this is to use a portable USB battery, otherwise known as a power bank. There are many units on the market, and I have tested many of them. Some of the cheaper units have falsified capacities, spiky voltage output which can damage devices and safety issues.
People looking for a good value power bank have been positively praising the Mi power banks. Last year, I had made a posting about the 10,400mAh version which passed my testing with flying colours.
Mi has since released an even larger version, rated at 16,000mAh, to meet the demands of more advanced users - read the full review to find out how it fares.