Poor quality product ... (see EDIT)

The product looks good.
I put him in charge upon receipt (or overnight).

First test this morning on the train, charging begins after 10/15 seconds (at first I thought the battery was not working).

In 5mn load, without using the phone (Galaxy S4), my battery went from 70 to 82%.

The supplied cable is USB type micro (compatible with most phones, except Apple) and is used in both directions (charging the battery and charging the phone Anker)

EDIT December 11:

After one use, the battery stops working. The battery recharges well (USB indicator lit during charging), but impossible to charge my phone (tested with several USB cable and several phones) => Back at Amazon with product refund.