Now this sounds cool.

A new security thread has been approved for the $100 bill, the Associated Press has learned, and the change will cause double-takes.

The new look is part of an effort to thwart counterfeiters who are armed with ever-more sophisticated computers, scanners and color copiers. The C-note, with features the likeness of Benjamin Franklin, is the most frequent target of counterfeiters operating outside the United States.

The operation of the new security thread looks like something straight out of the Hogwarts School of Witchcraft and Wizardry. This magic, however, relies on innovations produced from decades of development.

It combines micro-printing with tiny lenses -- 650,000 for a single $100 bill. The lenses magnify the micro-printing in a truly remarkable way.

Move the bill side to side and the image appears to move up and down. Move the bill up and down and the image appears to move from side to side.

"It is a really complex optical structure on a microscopic scale. It makes for a very compelling high security device," said Douglas Crane, a vice president at Crane & Co. The Dalton, Mass-based company has a $46 million contract to produce the new security threads.

The redesign of the $100 is about one-third of the way complete. The bill is expected to go into circulation late next year.