The set contains of 3 Black Pigma Micron pens with the broadest nib widths of this assortment: 1 x 08 (0.50 mm), 1 x 10 (0.60 mm), 1x 12 (0.70 mm). Pigma Micron pens are waterproof and permanent fineliners that are loyally used by designers, scientists, archivers, manga artists, cartoonists, illustrators and hobbyists. It is the recommended pen for Zentangle. The fine nib makes this pen ideal for creating both technical and artistic drawings. The unique Sakura Pigma™ ink will not bleed through paper, is permanent, waterproof, fade resistant, quick drying and pH-neutral.