The XVive U4 In-Ear Monitor Wireless System features digital wireless technology that delivers incredible audio quality, simple setup with plug-and-play operation, and it is also extremely reliable for all gigging musicians. It provides a full 20 Hz - 20 kHz frequency range with 107 dB signal to noise ratio to provide a clear, detailed audio signal at any volume level. This wireless system operates at 2.4 GHz ISM band for crystal clear broadcasting, ensuring the integrity of your signal on stage and it covers more than 27 meters (90 ft.) of range without any signal dropout. The rechargeable Li-ion batteries make the U4 wireless monitor system environmentally friendly and last up to 5 hours on a full charge. The chassis is made out of a durable and lightweight ABS plastic and metal parts that can withstand the rigors of touring and the harshest of climates. The U4 Wireless In-Ear Monitor System aims to take the complexity and frustration out of traditional wireless monitor systems. Of course you can combine multiple receivers with one transmitter by choosing one of six available channels. The U4 set with two receivers is an extremely useful bundle for duos that work with the same monitor mix.