ZIG Clean Color F pens are a dual tip water-based dye with a range of 40 colors. Also available in 6 metallic colors and 6 pastel colors, both being a water-based pigment, this make them suitable for dark papers. Tip sizes are; extra fine (.5mm) and a large (1.2mm) bullet point. ZIG Clean Color F are most suitable for paper. Sets include: 6, 12, 24, and 36. ZIG Clean Color F pen are great for illustration work, cartooning, and fine arts. Pair with our ZIG Blender or our ZIG BrusH2o for amazing blending and watercolor effects. Blending Tips:Taking two ZIG Clean Color F pens, for a few seconds gently touch nib-to-nib. Keep the two pens horizontal and ink will flow from the top pen onto the tip of the second pen. After using the blended pen, clean excess ink off onto a piece of scrap paper or towel.