Contain extremely fine polyacetal plastic nibs set in 0.5mm stainless steel sleeve for smudge-free inking. Disposable technical pens are 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. Sets are supplied in protective vinyl sheath.