Sakura Pigma Micron Pens are the perfect tool for precise line work. Ideal for artists, writers, and illustrators. Ink is waterproof when dry, perfect for use with watercolor! These pens offer lasting quality with archival, acid-free, fadeproof Pigma ink. The ink won’t feather, bleed, or clog, even on the thinnest papers. The pens are not refillable.