The Mi band is good fitness tracker because of the followingfactors: -
1.Price-Low
2.Durabilty-Water resistant & dustproof with IPS grading.
3.Features-Pedometer, Sleeptimer, Distance tracker and call-smsnotifier.
4.Battery- Last almost 30 days on singel charge way better battery than any other finess tracker in the market.
The only con is the Pedometer is not always accurate.
