Safecracker 40 Wooden Puzzle

The aim of this puzzle is to get each of the 16 columns of numbers to add to 40 at the same time. There is a base ring and then four rings that rotate on top, to add to the difficulty the top rings are notched, hiding or revealing the numbers below as they are turned, greatly increasing the number of possible combinations.

A unique wooden puzzle from a 1911 design called 'The Great Burglar'.

A picture solution is provided.

Difficulty level 4 - difficult

Levels run from 1 (Easy) to 5 (Very Difficult)

This is not a toy