Had a trackable tag or coin go missing? Not ready to give up on it yet? Or just got a precious coin or bug that you're not quite ready to send off into the world on it's own?
The DupleBug is a great solution - without a tracking number of it's own, you can add the tracking number from another item and send it out travelling instead.
Simply write your existing tracking number in permanent marker on the tag and send it out. Cheaper than a replacement trackable, you can re-use the tracking number you've already paid for. Because the tag is blank you can use it for geocaching.com trackables, or any other listing site (e.g. geocaching.com.au)