Ergonomic Wingnut Wrench (e.g. for Jigsaw)

I designed an ergonomic wrench to tighten and loosen the wingnuts of my wife's jigsaw. The normal wingnut wrenches you can buy are just sheet metal and can be quite painful for the spouses hands.
This little tool fits very neatly in your hands and is the right size so the nuts cannot be overtightened.

The wrench can be used for wingnuts in other applications as well ofcourse.
The tool is designed for an M5 wingnut as measured from my wife's jigsaw. Scale to size if necessary for your appli