Suitable for sketches or pen & ink drawings, these pens are unsurpassed in lightfastness. Pigmented Indian ink is waterproof and smudge-proof when completely dry. Ink formula is acid-free and ph-neutral, ideal for archival works. Set includes 8 black ink pens. Extra-superfine (0.1mm), superfine (0.3mm), fine (0.5mm) and medium (0.7mm) pens feature nylon tips to provide crisp, clean lines. Brush, soft chisel, soft brush and 1.5mm bullet tip pens allow for a variety of drawing techniques. AP Seal, non-toxic.