A nice little filter from Befaco, that's also kinda a mixer and sorta vca. Either mix three signals through the filter or take that filter out, and the vac triggers on input audio voltage, that's why I say "kinda".
Pretty straightforward build, though as typical Befaco there are a number of tight solder locations.
Calibration was a breeze, also.
And sounds pretty sweet. Will sit well in many mixes.