Making quite a picture with the phone outdoors and having the high brightness, the battery level drops quickly.
With this external battery, I no longer worry about it, the charge is relatively fast, count one to two hours for an iphone 5s for a full charge.
The design is very successful with a healthy weight without being too bulky. The circle of light is convenient to display the remaining battery level.
Only drawback, the product does not come with an AC adapter / usb but that of your original charger done very nicely.
This product is especially suitable for people who often travel and / or who do not necessarily have available electrical outlets.