High quality nylon brush, high quality watercolor brush, soft and durable brush head, 6 different brush heads, each one can be used for writing. Multipurpose watercolor pen is a hollow plastic pen that can be used to warm the pen tip, filled with water for solid or powdery pigments, used with watercolor crayons, markers and watercolor pencils. Portable watercolor pen just squeeze the barrel to control the ink or water flow. Quick, easy and fun painting with water mixing or adding inks. Our Watercolor pens are also completely non-toxic materials, odorless, and acid free. Rinse with water after use can be.