The listing, cOunterfeit currency detector pen has ended.
this pen can save you hundreds
This marker is a highly effective and inexpensive tool for detecting bad bills and deterring counterfeiters
You can carry it everywhere you go
Make a small mark on U.S. paper money
Light Mark: Bill passes test. Dark mark it fails
more details are in the package. Also works with many international currencies. Great for the listian collector. List price is $ 19