Battery Bank 4 x AA USB A SKT with Switch Black

In the space of two decades, USB has gone from a revolutionary way to connect peripheral devices, to a standard so common it’s used to power and charge all sorts of things.

By now you have likely heard of, and understand what a mobile power bank does. But in case you don't, here's the explanation. Effectively it's a high capacity battery (much higher than your mobile phone), which can be used to charge all sorts of devices from it.