Unknown Old Volunteer Pin Wonder Worker

Here is another pin from the same estate. It says "Volunteer Wonder Worker" and in the middle is a big "U." There were several other pins from this estate from American Legion, Nursing pins, Red Cross Pins, etc. I can't find anything about this at all. Could it be English? I did have a Scottish Nursing pin. It seems old and has a safety pin type of clasp. I just really curious about this piece.