A special quick-drying black ink, which is highly resistant to chemicals and water, was specially developed for these felt-tip pins to write on PolyPaper®. The pens can be used to permanently record information, and they are also excellent for writing on glass and plastic. The ink remains clearly legible even after repeated autoclaving. Cap with handy clip. Lab markers are the same as the lab pens, except that the marker has a wider felt tip.