What do the numbers on a ballpoint pen mean?

What do the numbers on a ballpoint pen mean? Here is the detailed answer.

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Any ideal what this number means? : r/fountainpens

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* Writes for almost a mile * Sturdy, well-balanced barrel makes this pen a favorite * No matter what size hand you have, the long barrel makes this

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Reference number for all nine brand of list of studied black ballpoint pens

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