Derwent Willow Charcoal is deep, rich, black and naturally water soluble. This soft yet strong medium glides beautifully and blends effortlessly with a uniform velvety texture. An artist’s essential for studies, life drawing and sketching scenes quickly, they"re also round barreled for an easy grip. Box of 25 natural vine sticks has a medium degree of hardness. Each measures between 4 and 6mm in width.