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. Brush tip pens combine the advantages of a brush and a drawing pen. Set includes 6 landscape colors: chrome green opaque, green gold, Indian red, indanthrene blue, May green and sky blue. AP Seal, non-toxic.