My note 8 always runs out of battery, as I use on Qhd display while using my phone. This case comes in handy as I can use my phone while it is charging. It has two functionalities. 1. Battery case. 2. Power bank. This case be turned on and off by clicking on the button behind the case. It's a bit bulky to hold on to. But it's useful when you really are out of juice and travelling.
Two way functionality