DOD FX80B

The FX80B Compressor Sustainer was introduced in mid-1985, and replaced the FX80 in DOD's FX-series lineup. The FX80B added a third knob to control how quickly the signal is compressed, allowing the user to have more dynamic control of the effect.

Controls: Level, Attack (5-200 ms), Compression (0-40 dB)

From the manual: "The FX80B Compressor/Sustainer reduce[s] the dynamic range of the input signal from an instrument. Dynamic range is the difference between the loudest and quietest portions of an instrument's sound. By "compressing" or squeezing the the loudest and quietest portions of an instrument's sound into a more compact range, you can control the signal better. Since the loudest and quietest portions of your notes are compressed, your notes sustain longer, the sounds seem tighter, and you can help avoid clipping going into other effects or your amplifier."

No box or manual.