An example of what navigation looks like on the Mi Band
The output and what it displays is highly customizable.

The Mi Band 4, just released last month, is selling like hotcakes. This little fitness band at a $30 price point offers features found on the more expensive FitBit bands. 

Besides the many useful stock features of the new Mi Band 4, independent developers have created apps to allow owners of the Mi Band to do many other things. One of the cool things that you can do with third party apps is display Google Maps directions on your wrist. 

The app, available from the Play store, is called "Mi Band Maps: navigation for Mi Band 3/4". 

With the app you can display highly customizable maps directions on your Mi Band. The app costs only 99 cents and at the time of this writing it had 4.2 out of 5 stars.