If the cell phone is a certain distance (which is called "guarder distance") from you, the sensor will ring or shake so that you can notice the potential theft or lost.

如果手机远离你一定距离(称之为“保卫距离”)，传感器会响或震动以让你注意到潜在的盗窃或丢失。

youdao

Here anti-theft device is also very good, it has "mind-reading" yo, the guest has come, the door will open automatically, ring welcome song;

这里的防盗设备也是很棒的，它拥有“读心术”哟：客人来了，大门会自动打开，响起欢迎曲；

youdao

There's a prolific car theft ring in Gaza and security officer Asharaf(ph), which is not his real name, says everyone knows who's involved.

NPR: Gaza Clans Occupying Political Vacuum

Uncovering an organized identity-theft ring was the last thing Grace Varnell thought she would do when she returned to college to obtain a nursing degree.

FORBES: How Credit Reports Can Protect You From Identity Theft

Last year, my office was able to file an indictment against an identity-theft ring for submitting phony tax returns in the names of more than 300 victims.

WSJ: Cyrus Vance Jr.: Why Your Tax Return Isn't Safe