TestFreaks tried the Lumsing 11000mAh External Battery Bank
A quote from the article:
Up for review today I have another portable battery for mobile devices and it's a big one at 11000mAh in capacity but what's even more interesting is that it has five USB ports which you can use all at the same time. The battery doesn't really have any specific name, it's from a company called Lumsing that makes many different products, this battery being just one of them. The Lumsing battery has five USB ports but they all vary in output from .5A up to 2.1A so you can charge a multitude of devices from small Bluetooth headphones up to tablets. Read on to learn more?Lumsing 11000mAh External Battery Bank Review @ TestFreaks