It is the generation of technology.Now every thing is done technically such as: -college admission, study, office work. etc.I am a engineering college student .my mobile phone is an important source for me to read.It is very necessery to alive my phone battery.so I brought a powerbank.some times because of power cut for long time troubles me to read.Now this problem has vanished.we also need a powerbank when we travel a long distance.we should buy a high capacity powerbank .It is a helpful thing for me.