http://www.jammer-buy.com/gps-jammer/c-25.htmlI think you must have seen the eavesdropping movie, with the development of eavesdropping technology, jammers also followed, people in order to protect their privacy, whereabouts, people choose to buy a portable jammer. Some room eavesdropping waves are weak. If you are not close to the source of the eavesdropping wave, it’s just noise and you can not hear it. Everyone has a whisper This is because the surrounding radio waves are easy to jump into and cause the intersection to be open. This is the starting point for finding eavesdropping equipment. Even if you receive a radio wave, such as stealing, the car will not stop. To eavesdrop, keep a straight line until the radio wave disappears and turns left and disconnected. There are many restricted areas in the urban area, traffic is very large, if safe driving, can be explored.