www.pathtags.com They are small (about quarter sized) coins. They are designed by the owner and can be left in caches bigger than a micro. Each coin has a number on the back that can be logged in on there website. Unlike a travel bug, you keep and collect pathtags. Some of the tags, like Kayaking Loons, The Francis Family, and Hollara (for example) are really complicated and filled with colors. Mine is a simple design that glows in the dark. If you purchase a design, you can trade on the website with different people. We have found about a dozen in different caches and put out about 50 or so. I've also traded online for about 20 more. They are a really cool way to personalize an item. If you would like, PM me with your address and I will mail you one of ours to start your collection. I'm designing a second pathtag for this spring. :)