If you are forgetful like me, you can use this inexpensive smart tag tracker to find your lost item like wallet, phone, keys or luggage.  Nut mini is thin, small and light.  The phone apps is easy to install and when nut mini is out of the safety range set, your smartphone will beep to alert you.

Although they never mention about putting the tag on kids, I  think parents with kids  can clip the tag to them when you go shopping but make sure you on your beep volume so that you can hear the beeping if your kid is out of range.

NUT Mini Gen 3 Intelligent Smart Tag Tracker