I should clarify that this is most likely NOT a tool to fix No Nonsense pen, but a tool made to fit into a NoNonsense pen to be used in the factory. Just as pens are great tools for writing, a pen barrel and cap make a perfect vehicle for a tool, easy to keep in a worker’s pocket and lots of space in the barrel for the tool. This black No Nonsense has a steel stylus on the nib end and when you unscrew the barrel, a round diamond shaped steel file is inside. The barrel has some light surface wear. The cap has more surface wear and a deep, small indentation just to the right of the clip ball. Measures 5 3/8 inches long. My gut tells me this was most likely a tool for a machine in the factory, not a tool for working on a pen. Interesting piece from the former factory in Fort Madison, Iowa.