Keep a bottle of this accurate, easy-to-use counterfeit currency testing liquid near every point-of-sale station. It's effective on almost any paper and leaves no mark on good bills. Nontoxic formula safely detects counterfeit ink. Leak-free applicator ensures mess-free results. Counterfeit Bill Detector Type: Liquid; Marking Color: N/A; Counterfeit Indication Mark: N/A; Currency: U.S.