What we have here is a state-of-the-art encryption machine. At least state-of-the-art as the state of art was just prior to WWI. During the United States' period of conflict with Mexico eventual father of cryptology, Colonel Parker Hitt, began solving intercepted cipher messages crossing the border. The picture Mexican Army Cipher Disk represents his code crackings condensed into a format easy for anyone to use in creating or solving coded communications.
The Mexican Army Cipher Disk consists of 5 concentric alder wood disks that convert letters to 2-digit numbers based on a key used to set the wheels prior to message composition. Over 386,000 possible unique key codes are possible. The larger cipher wheel measures around 6" in diameter and the wood is laser engraved with coding numbers. Maker Creative Crafthouse includes detailed usage instructions with purchase.