Ustka from XAOC Devices is an expansion module for the Eurorack mixer Ostrawa. The module picks up the individual VCAs of the mixer in pairs before routing them to the sum output. In short: with Ustka, Ostrawa becomes a quad stereo VCA. On the rear panel, you can use Jumper to define for each individual output whether the output level should be line level or Eurorack level. Due to its passive design, the module requires no power.