The ink inside is made of non-toxic material and does not contain any substances that are harmful to child health. Thanks to its super washable properties, the tenden can be easily removed by washing with water only without the use of soap. In addition, the remaining tracks can be easily cleaned by washing. There are holes specially designed to allow air passage through the doors. Thanks to this system, the ink inside the pen does not dry out. Thanks to the special tip protection system, the tip of the pen does not deteriorate easily. All materials used in the production of pens and inks contained in them are colored by using only food coloring. Plastic parts are also fully recyclable.