Hey friends Now you are going to know about power banks.If you have an smartphone or tablet then you may need power banks to charge your phone again. Now a days all latest mobiles are approximately giving capacity of nearly 3000 mah battery. So if you travel almost all the time in a day then you should buy a power bank whose capacity will must be 15000 to 20000 mah. If your phone loses battery capacity then you need a power bank and make sure that you are buying a branded power bank like Mi, Ambrane, Intex etc. But it is strictly prohibited to buy power bank at pilgrimage. And if you notice that power banks are selling in very low cost at local stores then please do not buy those. They are actually damazed or crushed and so they are only wastage of money.