Power bank also called mobile battery or external batery digita charging design thats look like a stick or our vault and that is fit in our pocket and we can use powerbank any where power bank is very good for store and safe our time we can use in train or and thats place where electricity not comes features is very good and we can charge power bank and store or charge our mobile phone nd this is 2000mah is very useful for busy person or whose not cache he electricity every where