A marker pen that the ink changes color when rubbed. Not only can you write letters, but you can also paint colors, so there is a wide variety of variations. After the handwriting has dried sufficiently, rub it with the rubber on the back of the shaft. The color of the ink will change.
The ink changes colour on the paper surface when rubbed, making it ideal for adding colour to notebooks and diaries, as well as creating 'wish lists' to list your dreams and wishes, and 'to-do lists' for work and private life.
