What is the screen unlock of the band?

The band and your mobile phone are bound together one to one. Within a safe distance, the band acts as your identity ID and it can be used to enter the unlock password or pattern and unlock the mobile phone screen, which greatly enhances the convenience while ensuring security.  Notes: This feature is available on mobile phones that have installed MIUI systems of Android 4.4 and above 

versions and on mobile phones that support Smart Lock with Android 5.0 systems. Some domestic mobile phone brands have made major changes to the Android system and this feature may not be available on such brands