The Aquash Waterbrush is a synthetic brush attached by a non-return valve to a hollow body which can be filled with water or colour. Ideal for blending watercolour pencils or applying watercolour, gouache or ink. The springy nylon tip is available in fine, medium, large and flat-tipped. The best way to describe the flat-tipped brush is that it's a flattened version of the broad tip.
An extremely popular item amongst all kinds of artists, particularly those on the move.