1íóthe writing trace of the pen will disappear spontaneously. 2íóhigh temperature and water can make the writing trace disappear faster. 3íóthe vanishing time may vary with material and size of the fabric and surroundings such as temperature, humidity and air circulation. 4íóuse for shoes industry, especially write on sport shoes for temporary marking. 5íówe have variety of outer tubes and nibs for your choice. 6íónontoxic ink. **use scope: pvcíónet clothingíópu-coatingíónapaíóblack skiníónyloníóreal fur materials back fur etc.. Medium box: 12pcs per dozen, 10dozens in one medium box, 12 medium boxes in one outer case.