So someone who has the same app has to be within range of the tile I assume? I have trackers on both my dogs. $130 per year subscription, GPS coverage and it advises me both on my phone and by email when they leave a perimeter that I define. Shows me on my phone exactly where they are anywhere in the world and anywhere in the world I happen to be, it shows me exactly where they are. Relies on no one else. I could put the tracker in my car and it would do the same thing. Other than the battery would run down after a few days so would have to be hard wired to keep it charged.