ConterfeitDetectPen. Counterfeit Detector Pen International Formula Smart Money Counterfeit Detector Pen International Formula. The same revolutionary technology in counterfeit detection, also available in an International formula! Dri Mark's patented design works on all major international paper currency, including (but not limited to): Euro Russian Ruble British Pound Hong Kong Dollar Japanese Yen Brazilian Cruzeiro Korean Won Indian Rupee Argentine Peso South African Rand U.A.E. Dirham Thai Baht U.S. Series 1959 & later (Not for use on Canadian dollar) Simply make a small mark on currency. A light or clear mark passes the test, a gray or brown mark means the bill is probably counterfeit. An easy to use, reliable and inexpensive tool. Made in the USA. U.S. Patent No. 5,393,556. Price: $3.00 Unit: Each Quantity: