The Sign Pen brush is a flexible point water-based dye ink pen. The richly saturated colors are fully blendable with water and other Sign Pen brush colors. Wear-resistant, pressure-sensitive and flexible tip can be diluted with water to get a full range of values. Great for feathering, Cross hatching, outlining, calligraphy and detailed line work. It will not dry out if left uncapped and can be cleaned with a paper towel. Acmi certified nontoxic.