4x Mixer
From MMM Wiki
4-input mixer capable of handling audio or CV signals.
Simultaneously available inverted and non-inverted outputs.
Independent attenuation for each channel
"Punch-in" toggle switch on each channel to allow for "pre-setting" an audio or CV source on the channel, then "punching" it into the mix for realtime dynamic CV or audio control. Or simply, a channel on-off switch.