The SW4 allows you to connect two mixing consoles to the same set of outputs, perfect for festivals or venues that switch from one console to another between acts. Each of the four channels features XLR inputs and transformer-isolated outputs to eliminate hum and buzz from ground loops, and they can be linked together to switch simultaneously. Channel-1 has a A+B mix function that sums both inputs together - allowing a wireless mic for the MC to be always active, while PFL switches and headphone outputs allow a technician to monitor any channel to ensure seamless playback. Since individual channels can be switched on their own, the SW4 can also be used to switch multiple wireless systems, playback devices, or any balanced audio sources.