A writing instrument — usually a ballpoint or fountain pen — whose body is made partially or entirely from transparent (and sometimes tinted) materials. This allows the pen's inner workings to be seen, thus demonstrating the way the pen works.

Originally intended for use in pen shops, they quickly became popular amongst collectors because of their limited availability and novelty effect. Demonstrator pen bodies are often made from inferior plastics rather than high quality resins, making them easily scratched and less practical than a standard pen.

Manufacturers commonly producing demonstrators include Waterman, Pelikan and Pilot. The transparent Lamy pens are not considered demonstrators, since they are not available in any other style; nor are pens merely containing a small cut-out window allowing ink levels to be seen.

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BrevityQuest 2006

Dem"on*stra`tor [L.: cf. F. d'emonstrateur.]

1.

One who demonstrates; one who proves anything with certainty, or establishes it by indubitable evidence.

2. Anat.

A teacher of practical anatomy.

© Webster 1913.