Selection of 4 Light Cool Gray and 4 Cool Gray Pigma Micron and Brush pens: Pigma Micron 01 (0.25 mm), Pigma Micron 05 (0.45 mm), Pigma Micron 10 (0.60 mm) and Pigma Brush. With these buildable grays you can add shading, depth, visual accents and layering effects to illustrations, drawings, bullet journal spreads and so much more.