Entrust Pro Counterfeit Pens -- Marker Detects Fake Counterfeit Money with Professional Round Tips, Universal Currency Detector (12 Pack) EASY and FAST - The unique formula in our Counterfeit Pens will instantly give you visual verification that a bill is real or fake. A simple mark on paper currency: dark mark means counterfeit, light mark passes test INSURANCE FOR YOUR BUSINESS - Just one detected bill and this product pays for itself instantly INEXPENSIVE and NON-TECHNICAL - Disposable pens can be discreetly stored in your pocket or purse. Other products require large manuals and power cords to detect illegitimate money. SAVE MONEY and your business from fraud and counterfeiters looking to scam you with fake currency. WORKS ON DOLLARS, Pesos, Euros, Yen and other paper based currency. Take one with you when you TRAVEL so you don't get ripped off dealing with FOREIGN CURRENCY you aren't as familiar with.