This is a clue towards the solution of the Centrifugal Puzzle Box which is a puzzle box that is solved/unlocked by spinning the box on a flat surface.
This 3D printed keyring (sold separately) contains embedded within it, using a special wax that is trapped within the keyring during the 3D printing process, a QR code and the word 'CLUE' above it (just to make it that bit more obvious), if the user is stuck while solving the Centrifugal Puzzle Box they can choose to reveal this clue by using an IOS device with a camera (iPhone, iPad, iPod Touch 4g) to read the QR code by using a barcode reader application (tested with an app called 'Scan') reveal the text "A=1 B=2 C=3" on the device's display which should help the user decode the message on the puzzles lid helping them to solve the puzzle and open the lid.
Please note that the keyring attachment (metal part) is not included.