Frixion Clicker (.5) Heat Erase Pen – BLUE – by Pilot Write, Remove and Rewrite. New Retractable model with side clicking action! New thermo sensitive gel ink that disappears with friction using the rubber tail tip on the pen with no residue and no tearing of paper. No cap to remove to get to erasing tip! Smooth writing gel ink This product is not recommended for signatures, examination papers or official documents. If pen is exposed to extreme temperatures (<-10C;>60C) , the ink will disappear. To restore colour, cool to at least <-10C in freezer and ink will reappear