I use it to test different solar devices I'm testing and it works great.
It is great for testing of both USB cabled and USB chargers.
And it is so frustrating to not know that a charging source is bad until your phone dies when you need it most.This device shows both the voltage of the charging source and how many amps it is passing to a phone when it is charging.
But when i plug in this it's working.
I have only had this item for a week, but in that time I have learned a lot about usb power sources, usb powered devices, usb cables, and connections.
I just received one as a present and all it does is read out voltage.
No power reading or capacity reading without a measurement of Amps.
No instructions included, and the the display gives you no hint as to what measurements are being displayed.
Pressing the small button on the side "cycles" through various functions (some of which "flash" and cycle through unidentified functions on their own), but again there is no obvious indication of what is being displayed.