In this era every one are using smartphone.so I also.but battery become a issue.so I bought a mi charger. And I buy this one.it is a great great power bank.i used it for cherging my smart phone.its pretty fast.mi is a good brand who sells great product at a cheap price.so its a nice product.i used it.its little bit heavy.black one I picked.it comes with a small usb to usb cable.and packing is also nice.