You can use this spy gadget to detect counterfeit money or to locate any hidden cameras in the vicinity that might be spying on you.
The RF detector in the pen alerts you with a flashing red light according to the signal strength of the wireless device it has located. You don't have to worry about turning the RF function on or off as the pen is always detecting and searching for RF signals for you.
A push of a button illuminates a UV light on the side of the pen that allows you to inspect possible counterfeit bills that might be passed off to you as genuine, making this pen a double threat to those who would use you as a mark.
Don't take chances. At this price you can't afford not to have one.