It is a "stamp" of the friction series which disappears when it rubs. Because you can erase it, you can easily erase it and push it back even if there are changes after pressing it in the notebook. Please wipe off with the rubber at the rear of the main unit. Penetration mark type. The friction stamp is a stamp that can be erased. Please do not use for things such as certificates, addresses etc. that should not disappear. We use some different color products for detailed image. If we leave in place where it becomes 60 degrees Celsius, ink becomes colorless. When it becomes around -10 ° C, deleted handwriting may return.