This PU uses a piezo sensor housed in the wheel of a bridge height adjuster. Because the cable(s) can be removed, it is possible to rotate the adjuster easily. It’s offered a single (one wheel) or double (two wheels) sensor model.
This japanese PU has been offered since 1987, but is almost unknown outside Japan. Eddie Gomez is an endorser, and has provided a soundclip playing the CPS-DB for Yamahiko’s website.
yamahiko video on youtube
please check it!