A near as makes no difference mint condition example of the Boss' SYB-5 Bass Synthesizer. All the bass synth tones you could ever need in one incredibly robust enclosure.
The BOSS SYB-3 was the world’s first bass synthesizer to be packed into a compact pedal, and it found favor with experimentalists and tone aficionados alike. Today, the next-generation bass-synth pedal has arrived: the SYB-5. Utilizing the latest in DSP technology, the SYB-5 faithfully reproduces the classic sound characteristics of analog synthesizers with enhanced punch and power.