Contain 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 nonbleeding, 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. Packaged 12/box.