This brush pen is ideal for use with watercolors. Fill the reservoir with water, dab the brush tip in your paint to get some color on there, and start painting! Change your stroke styles to create interesting line variations, and use blending techniques to blend colors and create blurred effects. With this water brush pen, you can paint beautiful watercolors without the hassle of using a brush and separate water container. When filing the brush, twist the tip section clockwise to remove it from the barrel.