These are good microphones, but in my country (Russia) 4G networks work at their operating frequency, so microphones catch noise. The transmitters themselves are light, very good power consumption, I think that the batteries will last for about 20 hours. In transmitters, the inclusion button is poorly implemented, it eventually breaks down and it is rather difficult to replace it, but it is possible. On aliexpress there are options. The sound transmission and sensitivity of these microphones are at a good level, at a line of sight, I think you can safely talk about 50 meters. If you need inexpensive microphones, then this option is good, but if you expect reliability and range from microphones - look at other options.