In the early days, signal jammers could only block a set of frequencies, such as 2G, while complex jammers could block several types of networks at once, such as 2-3G. Now this jammer is even more powerful.As a multi-function desktop jammer, this product can block 8 frequency bands. Such as all cell phone signals: GSM/CDMA, 3G, 4G. It can also block GPS,WIFI and other signals. It has 19W , the jammer range is very large, it's block signal output is stable. Have separate frequency switch, you can choose according to need to open or close a certain frequency band. It also has power adjustable function, you can adjust the range of interference as needed.