Contains extremely fine polyacetal plastic nibs set in 0.5mm stainless steel sleeve for smudge free inking. Ideal for precision drafting, free-hand drawing, or any design work. Water-based pigment ink is non-bleeding, waterproof and fadeproof. The acid-free, archival quality ink is also quick drying and lightfast. These disposable technical pens are offered in five line widths. (0.1mm, 0.2mm, 0.3mm, 0.4mm and 0.5mm) Sets are supplied in protective vinyl sheath.