The Roland M-VS1 Vintage Synth Sound Expansion module is a 1U rack (aftertouch and velocity sensitive), 28 voice (8-part multimbral) digital synthesizer (editable via MIDI only), featuring an oscillator (254 samples), resonant low|high-pass filter, dedicated (4-stage) pitch, filter, and amp envelopes, dual LFOs (saw, sine, square, random, S/H, triangle waveforms with attack|decay), portamento, reverb/chorus, 255 presets, 8 rhythm sets, mix input, and MIDI.