The Pigma Micron Pen is the first fine-point writing instrument offering a water-proof, quick drying, black pigment ink. They are ideal for technical drawing, graphics, drafting and fine line illustration. Unlike dye-based ink found in most pens and markers, Pigma pigment ink is of archival quality, waterproof, fadeproof and smudgeproof on porous surfaces when dry. It does not feather and will not bleed through paper. Excellent copy machine reproduction.