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The RSF Expander II rack mount modular synth was manufactured as a companion option module for the Kobol Expander I synthesizer. The 19" 3 U space unit features a Ring Modulator, Envelope, a VCA, an LFO, Mixer with 3 inputs and 1 output. Additionally it has a Sample & Hold module with internal or external clock, a Noise Generator, Voltage processor that is delectable Linear or Logarithmic, Voltage Inverter, Gate Delay, an Envelope Follower, Lag Generator, and finally 2 multiples."