Precise Hi-Tecpoint technology combined with Frixion ink delivers an incredible writing experience. Erases cleanly by friction-generated heat, leaving no debris. Uses the same ink to write and over-write. Slim design and refillable. Extra fine 0.5mm tip. This product is not recommended for signatures, legal documents, examination papers or other documents where writing needs to be of a permanent nature. To avoid accidental erasure, do not leave writing where it may be subjected to high temperatures for a prolonged period.