A little history on the Letterbox and Letterbox Hybrid,
"A letterbox is another form of treasure hunting using clues instead of coordinates. In some cases, however, the owner has made it both a letterbox and a geocache and posted its coordinates on Geocaching.com.There must be a stamp inside a letterbox hybrid. It is not an item intended for trade; the stamp is meant to remain in the box so that visitors can use it to record their visit. To read more about letterboxing, visit the Letterboxing North America web site."
Letterboxing has been around since the 1850's, when it was first introduced in England. It originated with a bottle and a business card. Eventually, it evolved into something very similar to geocaching in the idea of finding a hidden container. Beyond the idea of just finding the container, the use of rubber stamps and logbooks came into use. Typically, there is both a rubber stamp inside the letterbox container that is used to stamp the user's personal stampbook and the user's personal rubber stamp that is used to mark the letterbox logbook. Letterboxing became more common in the U.S. after an article in a 1998 issue of Smithsonian magazine.
Letterbox Hybrid geocaches developed as an alternative to the traditional cache. It combined the written clues guiding the geocacher to the container for those who want to do that, as well as the coordinates for those who just want to go after the container without the clues. Letterbox Hybrid's also include a stamp in the fashion of a traditional letterbox that is not to be removed from the cache.
The cache is near a corner fence post and has some swag, a log book and a stamp and stamp pad for you to enter into your personal log book if you so desire. Please wipe off the stamp when you are finished and enter your own stamp in my log book.