Double your capabilities. Powerful LED with reusable ultraviolet light cap makes checking UV security threads simple. Highly effective on U.S. and foreign currencies, passports, credit cards, cashier?s checks and money orders. Chemically sensitive ink enables quick and easy currency tests. An amber mark passes, whereas a dark brown or black mark fails. Operates on AAA batteries (included). Counterfeit Bill Detector Type: Pen; Marking Color: Amber; Counterfeit Indication Mark: Black; Dark Brown; Currency: U.S. and most foreign currencies.