Faber Castell Graphite Aquarelle pencils are watersoluble, which makes them ideal for preliminary sketches for watercolour drawings as well as for grisaille-effect watercolour graphite drawings. The pigments dissolve completely when lightly brushed with water. The leads are 3.3mm diameter and come in five grades: HB, 2B, 4B, 6B and 8B. This pencil is an 8B.