Fine point, 0.7 mm Black Thermo-sensitive gel ink formula disappears with erasing friction Smooth-writing gel ink Erasable pens are not recommended for use on legal or official documents. Do not expose to extreme temperatures less than 14 degree or greater than 140 degrees fahrenheit If pen is exposed to temperature that reaches 140 degrees the ink will be colorless when writing. To restore color, cool to at least 14 degrees in freezer and the ink will again write in color 3 per pack
