This a property marker pen combined with a UV lamp which enables an invisible mark on all property Ideal for marking phones MP3 players laptops etc It can also be used to mark household items such as antiques televisions etc with postcodes or phone numbers Police routinely check stolen property with UV lamps The UV lamp can also be used to check for fake bank notes travellers cheques credit cards & stamps The ultraviolet lamp detects special marks made with fluorescent ink which are invisible in normal light Supplied in multiples of 24