The Safecracker 50 puzzle is an extremely tricky piece and a serious step up in difficulty from Safecracker 40.
The aim is to align the 16 columns so they each add up to 50 at the same time.
There is one base layer with four rings on top that rotate. Each of the four top rings is notched so they either hide or expose numbers on the ring below. In total there are over 65,000 permutations but only one correct solution!
Made in the US from maple and cherry this puzzle measures 130mm in diameter.
The solution is included.