BIAS BS-2 I confirmed it works by tapping it with my finger, using both a 9V power supply and batteries. I haven't checked FT/SW and EXT.IN. It's old, so I think it's best for someone who can do their own maintenance. There are some minor scratches, but the condition is relatively good. The BIAS BS-2 was an original percussion synthesizer (also known as the "Pyun Pyun Machine") sold by Ishibashi Music around the 1980s?90s. It's an instrument that detects "vibration" with a built-in sensor and produces sound. You can create thick, impactful sound effects unique to analog with simple operations. Responding to requests from musicians, noise was added to the model originally released as the "BS-1". Initially, it was designed to be attached to the rim of a snare drum and triggered by the vibrations of the shot. However, it also allowed for sound generation via foot switch and external trigger. In reality, it was widely used by people other than drummers, and became a popular and valuable instrument, especially among dub and reggae musicians and DJs. Electronic Drums Analog Synth YMO Yukihiro Takahashi