By now, you should know how these videos work.

nasrojee:
How Gretel 6000mAH battery Beat Oukitel K10000 Pro?
Check the video:

https://www.youtube.com/watch?v=qutlRQ9moZQ

bobo65:
Wetin I wan dey use 10kmah for

Na WA o

Good question, and I bet you these batteries will start degrading in 6 months, it happens to every mobile but I notice these smaller Chinese manufacturers tend to use cheap cells for these phones, I guess that's how the keep cost low..

Save your money, buy a device like the redmi note 4x / redmi 4x.. reputable company, Slim, better hard ware,powerful battery; unless you live in Sambisa forest then you don't need a brick with 10kmah..