Mi Band is a fitness tracker device additional fiture is phone incoming notificatio. It having good vibaration when ur phone receving any type of notification. I bought Mi band last month From mi store. Its very afordable price and its charging upto 30 Days. It having another fiture like sleep data track and alarm bid of under 30 minutes. Its working on phone with android 4.4 up and the application name was Mi fit. Overall it is a good device for buying those people who want to earn fitness tracker.