Very simple, and does exactly what it needs to doArvosana 5/5
I bought this on sale for 15€, which was a very nice price point for the spec. I use it as a backup for if I've run out of power (or a friend has run out of power), and for charging for example kindle (which always runs out just when you're about to read something in bed, so a power bank is preferable to a walled power cable). The bank is extremely simple. USB C charge, discharge, smart enough to know which (no in/out ports). It's a minor inconvenience there's no USB A port on the device, but this is easily worked with.
Bomadeno