"THE ONLY PATENTED COUNTERFEIT DETECTOR PEN, DETECTS AUTHENTICITY INSTANTLY" Works on U.S. and most international currencies. It's so simple!This patented chemical formula leaves a temporary CLEAR or YELLOW mark if the bill is good. Leaves a DARK MARK if the bill is suspect.Smart Money - Counterfeit Detector, Made in USA.Patent #5,063,163. Mark paper currency - yellow or clear/currency is good; brown or dark/currency is suspect. Use in addition to standard detection methods.Store product in cool, dry place. Replace cap immediately after use. Note: While no method of counterfeit detection is perfect, the Smart Money™ is an excellent deterrent to the passing of counterfeit currency and will detect a great majority of false bills. We recommend that this product is used in conjunction with other detection methods. SMART MONEY™ is effective on currency worldwide EXCEPT Canada and will not detect currency dated before 1959. SMART MONEY PEN SMPRegular price: $9.99Sale price: $6.99, 3/$12.99