The Sennelier Ink Brush Pen features a brush tip made of real fibers, ensuring a fluid, flowing application of color. The flexible brush tip allows you to create extremely fine to very wide lines (up to 10mm) with a continuous flow of ink, by simply varying the pressure of the tip on the paper. A wonderful tool for watercolorists and illustrators looking to harmoniously complete the details and highlights of their works in watercolor, this brush pen is equally suitable for lettering, journaling, painting and watercolor.Pigment-based, environmentally friendly ink is exclusive to Sennelier, Synthetic fibers ensure that application of the color is fluid, constant and linear, Slim design is very close to the shape of a brush