These Sakura Pigma Micron Fineliners contain Pigma ink, invented by Sakura in Japan over 25 years ago. They are considered essential for archival quality illustration projects, offering artists and designers smooth flowing ink, deep colors, and very stable pigments. This permanent, fade-resistant, chemically stable, pigment-based ink will not bleed or run if liquids are spilled on or applied to the document after drying. It is universally compatible with other media, such as watercolors, oils, and acrylic paints. Made in Japan, these fineliners are the most reliable, permanent ink-based disposable fine liners on the market. They offer smooth flow, strong deep color, and very stable pigments, and eliminate damage from UV rays, chemical degradation, and pollution from contact with oils and other chemicals on papers.