I have three of these units that were given to me.
I would never have bought them for myself.
These depend on BlueTooth being enabled along withthe app on mobile device everywhere. If nobodt meets these requirements they do nothing. I live in a rural setting and if I had one in my vehicle and it was stolen it would probably never be found.
Also BlueTooth, for some dumb reason, is the most battery sucking protocol/app you can run on a mobile device and most just turn it off after discovering their battery drains about twice as fast as without it.
I have three, and other than spying on somebody, find them completely useless so far. User created networking is quite the concept but for the once in a lifetime I might use it to actually find something the batteries will most likely be dead after the six month expected life of a CR2032. At least you can buy these batteries Chinese for less than a buck now.
There are some YouTube videos demonstrating testing a few people did with them. Most found them cool, but useless.
Even with a device located by your own mobile device you play the hotter/colder game as BT has no directionality. These are not GPS based and have no other locating abilities other than signal strength from a single point.
Tracking your teenagers or wife? in larger population areas, may be a better use.