I had one or two of these for my two cats. The problem is: you want a collar that opens and falls off when the cat gets stuck somewhere, so that for heaven's sake it doesn't strangle itself in it. That conflicts with the desire to have a collar that you don't have to go looking for yourself every other day and, in the worst case, can't find! After two months, I could no longer find one of the trackers and ordered a new one. After a few weeks, that one also disappeared again, never to be seen again. And finally I gave up with these things. I'd rather the cat lived than know where it was. Unfortunately, the realisation was always expensive.