Fantastic and unique puzzle based on a 1911 design. The object is to get each of the 16 columns of numbers to add to 40 at the same time. Can you find the combination? There is a base ring and then 4 rings that rotate on top. To complicate matters, the top sets of rings are all notched, so they will expose or hide some of the numbers on the ring below as the rings are turned. Makes for a lot of possible combinations! Ergonomically sized to fit the palm nicely. This will come unsolved in the package, but included is a picture of the solved puzzle. There is only 1 possible solution.