The portable cell phone signal blocker is small but powerful. The blocking radius of a portable phone is not as narrow as that of a large portable computer. Its working range can be from 10 meters to about 100 meters. The mini jammer is powerful and effective, and can effectively disable any WiFi network, GPS device and cell phone signal (on GSM, CDMA, DCS and 3G frequency bands) without interfering with any other electronic devices. The highly portable size and different power buttons allow users to quickly turn the device on or off to immediately interfere and remove interference. This portable signal jammer is very easy to operate and carry. It is an ideal security and anti-security device. It is very simple and one of the best signal jammers we have tested.