Winsor & Newton watercolor expertise in a marker! These markers deliver precision and control and are compatible with all Winsor & Newton watercolors and mediums. Their lightfast formulation offers optimal performance, transparency and brightness. Each twin-tip marker has a flexible brush tip on one end and a fine point tip on the other end. Once a drawing is made with markers, it can then be transformed into a watercolor painting by applying water with a brush. The sooner water is applied, the better the resulting washes will be. Colors can be mixed either on the paper or on a palette. There is 3ml of ink in each marker.