Tombow Dual Brush Pens, Grayscale Palette, 56171, 10 Pen Set. Set includes 9 grayscale pens and one blender pen. Pens have two tips, a high-quality, flexible, nylon fiber brush tip and a fine tip. Water-based ink is blendable, odorless, non-bleed and acid free. Resilient nylon brush retains it's point, stroke after stroke. Blend colors easily. Tips will self-clean after blending. Create subtle washes by dipping brush in water.