“The 90s reissue of the Electro-Harmonix Bass Balls Envelope Filter (bass/guitar) pedal. The Bass Balls’
twin dynamic filters track picking dynamics at slightly different
frequencies, creating shifting peaks and notches that simulate human
“Distortion mode further emphasizes vowel-like overtones
dynamic responsiveness, making Bass Balls the ideal accessory for bass
or guitar. Great sounding — (IMO) better than the new Nano Bass Balls.”
More information here.