Special black ink obscures private information. Perfect for hiding personal information on mail, documents & packages. Also useful for prescription bottles, price tags on gifts & sensitive documents. Covered information cant be easily read, scanned or copied. Works best on printed black ink. Identity Theft Secure Stamps use a special pattern to hide confidential information & is a quick & effective method of identity theft protection. Stamp Type: Message; Message(s): Obscures Data; Ink Types: Pre-Inked; Number of Lines: 1.