Dri Mark 351B1 Counterfeit Bill Detector Marker Pen, Made in The USA, 3 Times More Ink, Pocket Size, Fake Money Checker - Money Loss Prevention Tester & Fraud Protection for U.S. Currency (Pack of 1)

The Dri Mark Counterfeit Detector Pen is your best first defense against loss due to counterfeit. An essential for any retail business accepting cash. Simply uncap the pen and make a small mark on US currency. If the mark turns dark brown or black, the currency is suspect. If the mark remains light yellow, the bill passes the test.