Writes on all plastics, glass, metal, wood, paper and cloth, including Teflon® fluoropolymer resins.Precision seal valve provides smooth ink flow and preserves the pen’s life, even if left uncappedWhen dry, the solvent based ink is temperature resistant from 0 °C to 155 °C (32 °F to 310 °F)Markings are insoluble in water or hydrocarbonsResists many solvents, but is easily removed with alcohol or acetoneTEFLON® is a registered trademark of The Chemours Company FC LLC and used under license by Bel-Art Products, Inc.