◇ Mitsubishi Dermatograph No. 7600 Pink, Black, Orange, Indigo - Set of 4 The ingredients and quality differ from regular colored pencils, allowing you to freely write on smooth surfaces such as metal, glass, vinyl, celluloid, cellophane, leather, and human skin. These were found while cleaning out my parents' home. I believe they are quite old, but I hope someone who needs them can use them. Thank you for looking.