Rotring Rapidographs were primarily conceived as technical drawing tools; their special feature lies in being fillable with India ink via a piston, which was indispensable before the CAD era for building plans and tracings. The pens are regarded as susceptible to failure: they often start with difficulty, gum up through drying ink and react sensitively to too firm pressure. A dating to the 1960s/1970s seems plausible. To what extent they are classified as worth collecting beyond the technical use is judged inconsistently among collectors.
