Battery and external charger 12000mAh

Small and relatively low weight, this case perfectly fulfills its functions.
It is recommended to break in the battery discharging thoroughly before recharging completely this several times in order to extend battery life, and balance the elements (given the scale and capacity, it must be of four cells 18650 3000mAh each, in parallel).
A row of small blue lights indicate the remaining charge. A push button activates the outputs.
These are two in number, format Usb, including one for Apple.
I use this external battery casing (for Tenda wifi router), and as an emergency charger for tablet Nexus 7 (2013).
The set comes without mains power supply, I recommend 5V and 2 amps for fast charging.
This product is well made and works perfectly, with good maintenance charge.