4-band interference can generally have 2-3 types of interference signals, and the interference range is about 10-15 meters. This type of cell phone blocker is very popular in small-scale business places such as restaurants and hotels. It is generally portable and is mainly used in various examination rooms. , schools, gas stations, conference centers, hospitals, prisons and other places where the use of mobile phones is prohibited. The signal interference radius can be adjusted, and the coverage area is large. When using the wireless signal jammer device, in order to avoid the wireless signal jammer from causing interference to some electronic equipment, it should be kept as far away from the following commonly used equipment as possible: stereos, wireless microphones, radios, computers, TVs, Wi-Fi routers, etc.