A Travel Bug is a registered trademark of Groundspeak, Inc. used to describe a dog tag used in Geocaching. It is moved from cache to cache, with a unique tracking number allowing its movements to be tracked through their geocaching website. Some tags are fastened to an object, known as a hitchhiker, before they are released into a cache. Travel bugs have also been used as advertising to promote Jeep or to increase diabetes awareness. A free service known as Geokrety is also available but this is not affiliated to Groundspeak.