The Xer Dualis from Noise Engineering is a compact four-channel stereo mixer for audio signals. The four channels process either stereo or mono signals, the latter normalized to the right channel when using the left inputs. Each channel has a volume control and a mute switch. The module is perfect for combining the sum of several (stereo) signal sources, or to act as a submixer for effect returns in larger systems. The signal output is in stereo.