The OEM Counterfeit Dual Detector Pen DRI351UVB is designed to detect all counterfeit currency, including both old and new U.S. bills. This pen features a special patented formula that identifies bad bills effectively. It includes a UV light for proof positive detection on new bills and also validates foreign currency, Traveler's Checks, and credit cards. Fast and efficient, this tool is essential for ensuring the authenticity of currency.