The Alyseum MS-VCA4I &  MS-VCA4O Eurorack modules are two dynamically controlled, multi-input and multi-output mixing modules controlled by the MS-MATRIX module.
  
The MS-VCA4I adds mixer functionality and increases the number of inputs available on the MS-MATRIX, whereas the purpose of the MS-VCA4O is to add mixer functionality and increase the number of available outputs on the MS-MATRIX. 
Of course both the MS-VCA4I and MS-VCA4O can act as standalone modules, but why miss out on the unique preset functionality that their combination with an MS-MATRIX provides?
  
Up to 2X4 modules can work together via an IR link connection, creating a powerful behemoth of immense functionality for your Eurorack system.
            
Features:
   >    Quad VCA type V2164 :
           >    Wide signal range: ±10 Volts
           >    -92dB Isolation between any pair of channels at 1 KHz
           >    Low distortion: 0,02% 
           >    Low noise
           >    High bandwidth DC up to 20KHz
   >    Low offset output buffers.
   >    Direct VCA control by potentiometer with window LED.
   >    32 presets storage in flash memory, selectable :
           >    Manually via the MS-MATRIX front panel.
           >    Using CV via the MS-MATRIX CV input.
           >    Using MIDI Note or Program Change via the MS-MATRIX MIDI Input. 
   >    Optical hi-speed infra-red (IR) data emitter and transmitter to : 
          >     Chain more than one MS-4VCAI modules.
          >     Chain more than one MS-4VCAO modules 
          >     Zero HF noise
          >     Zero cables
   >    Polarised power header and protection against reverse polarity.
   >    Eurorack 8 HP wide.