The Pentel Aquash Waterbrush features a synthetic brush attached to a hollow body that can be filled with water or color, ideal for blending watercolor pencils or applying watercolor, gouache, or ink. It has a springy nylon tip available in fine, medium, broad, and flat-tipped sizes. The flat-tipped brush is a flattened version of the broad tip. This popular item is suitable for artists on the go. Fine, medium, and broad tip brushes are also available as a set of 3.