The U.S. has fallen behind other countries’ efforts to police the use of sales-suppression software known as tax zappers.

That’s according to Richard Ainsworth, a tax law specialist and adjunct professor at New York University Law School and Boston University School of Law.

When a retailer plugs a tax zapper into a register, the technology can essentially make certain transactions disappear. Businesses can then underreport their sales in the hopes of lowering their sales tax bill.

On this episode of our weekly podcast, Talking Tax, we hear from Ainsworth about the widespread use of tax zappers. He tells Bloomberg Tax staff correspondent Michael Bologna about what other countries have done to crack down on zappers and the approaches some states are taking to do the same.