Coloring your artwork anytime and anywhere is easy with the Koi® Coloring Brush pens! These pens perform similar to an artist brush. Make fine, medium or bold brush strokes just by changing the amount of pressure to the nib. The durable tip will quickly spring back to its original shape! The odorless, water-based solvent facilitates smooth blending and layering of colors.Koi Coloring Brushes are a convenient way to add vibrant color to any sketch, journal, cartoon, illustration, or rubber stamps. The 48 dye-based, vivid ink colors blend easily to create a multitude of hues and effects. Use the colorless blender pen to blend different colors together, create seamless washes and color gradations.