There’s also a tag called Byte Tag that’s relatively inexpensive ($10) to buy and the service is free. It works all around the world. They put a QR code and a URL onto the tag that can be scanned by whoever finds your dog. As soon as they do, you get a notification with their GPS coordinates and they get whatever info you’ve allowed shared like phone number, health info, instructions if found, etc. No batteries etc. It works great.