The Cobra Tag actually works both ways so if you’ve got your keys but have lost your phone, you can also use the tag to make your phone start ringing. There are plenty of other applications for the Cobra Tag, not least a host of juvenile pranks involving unsuspecting friends at weddings and the theatre. They won’t know where the ringing’s coming from.
Another useful feature, meanwhile, is the PhoneHalo application which can be set to lock your phone when it’s out of range of your tagged item. You’ll also get a reminder if you’re leaving your valuables behind and you can also check in with their GPS coordinates to find out where they are.
The tags are not restricted to keys either - you can attach them to anything valuable from a wallet to a computer bag. Though if you can’t find something the size of a computer case, you’ve probably got bigger problems.
All for US$60.