If there were any danger of confusing pens for writing with other kinds of pens (light-, sea-, pig-) the phrase “ink pen” might be useful, but it seems to be mainly a way of saying “not a pencil.” Plain old “pen” will do fine.
This is the ten-year anniversary of the Common Errors in English Usage calendar. To celebrate, we are bringing back some of our favorite interesting, funny, but sometimes merely silly entries through the years before going on hiatus in 2016.
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