The U4 personal wireless monitoring system delivers great-sounding audio to your Dream Earz in-ear monitors. Enhance your stage performance with freedom from wires with U4’s easy-to-use and portable plug-and-play design. Built using the highest quality components housed in a durable metal chassis ensures reliable wireless performance at every show. In situations where multiple “mixes” are needed on stage, each unit has 6 select-able channels for creating up to 6 individual discrete mixes. If you use more than one transmitter, The receiver can switch between different sound sources by simply changing the channel selector.