The line thickness of the fibre needles depends on the tip design. As a consequence, there are types, especially among the fibre gratings, whose line thickness is not a fixed value due to their cut tip, but falls within an interval. In the case of conical and needle-tipped pens, on the other hand, the line thickness is fixed.

Automatic pressure equalization prevents the pen from leaking on board an airplane.

Pigment-based ink: indelible (in accordance with ISO 14145-2 standard), lightfast, and waterproof on paper.

Exceptional lightfastness: The writing remains legible even after years.