The Universal wrench is a Wenger exclusivity and part of the special S557 for example; usually this tool is much seen on the knives in the 1980s so it is up until today a very used and known tool.
On the pictures you can see many types that show changes on this tool and some production variations. It is a solid function and used to turn bolts and screws. One of the sides of the bolt will go along the
flat section and one of the edges on a bolt will go into one of the cut notches and then one may turn.
It is easy to use and I do not need to show it is action.