Before buying, you need to know which signals you want to block. Ordinary mobile phone signals (2345G) can be selectively blocked. If you only block 2G or only 345G, this can be adjusted before leaving the factory. In addition, there are 2.4GWIFI, 5.8GWIFI, VHF, UHF and other frequency bands. Here we need to explain the functions of each signal frequency band. In short, 2G is the frequency band for making phone calls, and 2345G is the frequency band for mobile Internet access, so it depends on the specific shielding frequency band requirements.

The appearance of the mobile phone signal jammer can be divided into external antennas and built-in antennas. In general, the external antennas extend outward because of the external antennas, so they occupy a larger space than the built-in antennas. A little; just because of the antenna extending outward, the effect of the external antenna is more stable.