Powerful yet compact UV flashlight reveals UV sensitive security markings in 1996 series or new US coin denominations greater than $1. The counterfeit detector pen detects bad bills by marking a line on the bill; if the mark turns dark, the bill is suspect. The UV light also works on many foreign currencies, major credit cards, passports, traveler's checks, and much more. Counterfeit Bill Detector Type: UV light and watermark detector; color change ink; dial color: amber; false indication mark: black; dark brown; currency: USA