These power banks are very nice.
They charge quickly and hold a charge when not used for a bit.
I can get a full charge from 10% to 100% on my Galaxy Note 4.
They will fit in your pocket, daypack, bag or purse very nicely.
You can use them to charge any of your USB devices including, phones, headsets, camping lights, headlamps and so on.
They also feature a nice little LED light that you can activate with the press of a button.
Overall I am very satisfied with these and would not hesitate to recommend them to anyone.
Quality - A
Manufacturing - A
Functionality - A
Design - A