This invisible ink pen is used to detect, identify, and return stolen property in the event of a burglary. Each invisible ink marking pen contains invisible permanent ink. It''s safe and reliable and easy to use. It has a hard tip point which is superior to the felt tip which will fray and get out of shape over time. This products marks on all surfaces including glass, paper, wood, plastic and cloth and is invisible to the naked eye. The pen is great for game playing in the dark with the aid of a blacklight. The ink is visible under ultraviolet light for easy identification by police, detectives, and pawn shops. Marked items are hard to fence and evidence of guilt is apparent when thieves are caught. Use your driver''s license number along with your state abbreviation to mark on your property. This is an easily recognizable number to law enforcement agencies and is the most consistent mark of identification for personal property. Complete the process by keeping a log of what you have marked so you have a record of inventory. Our business is governed by by customer feedback. If you are satisfied with the way we handled your order we would appreciate you giving us a positive feedback when you can so possible customers can be assured they are dealing with a reputable seller on Amazon. Thank you Acme Enterprises