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
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.