Faber Castell Set 6 Watersoluble Graphite Pencils + Paint Brush These graphite pencils are water soluble. It is ideal for preliminary sketches for watercolor drawings and for mixed watercolor and graphite techniques. It has an extra 3.3 mm diameter and is break-resistant. Include five different lead hardness: HB, 2B, 4B, 6B and 8B and a watercolour brush size 6. Brand: Faber Castell