Set Contents: Pencils (HB, 2B, 4B, 6B, 8B) x 1 each brush; Features: Water soluble graphite pencils for artists. You can enjoy the watercolor expression. It is water soluble so it doesn’t leave behind any residue after drawing, so it can be used for rough sketching in watercolors. High quality water soluble on all hardness. It achieves a smoother expression. 1.5 inch (3.8 mm) diameter graphite core.