[1]environmental protection,not any poison [2]auto vanishing pen is best used by shoes industry,especially use in sport shoes for temporary marking [3]the writing will disappear spontaneously,the disappear time can adjust [4]we have multi-design. warning [1]auto vanishing pen is the same with disappearing ink pen and air erasable pen in some condition. [2]use the air erasable pen in its available time. [3]please use "the water" or "clearning pen" to get rid of the writing,if the writing do not disappear on normal situation. [4]the disappear time is limited to the material,air wet condition,temperature, and so on.