Set with 6 shades of grey from Koi's rich colour palette. 
By holding the tips of two brush pens together you can easily mix the colours. The ink flows from one point to the other. 
You can use the Koi brush pens by Sakura for hand labeling, bullet journaling, illustrations, sketches, cartoons, colouring pictures, comic art and so many more creative applications. Koi Colouring Brush pens have a flexible, sturdy brush tip, which allows you to easily draw different line thicknesses by adjusting the pressure on the tip. After use, the brush tip returns to its original shape. The ink is water-based, which makes it possible to create beautiful colour gradients by drawing different layers on top of each other or by holding the dots together. The ink can also be mixed with water. Use the Koi Water Brush with a built-in water reservoir that allows you to watercolour on the go or use it with another fluid. 
Available in various versions.