Garden (stringed) panels for generating acoustics. By plucking, rubbing, tapping or even bowing, those micro-acoustic sounds become amplified and effected by the "Folktek Alter" in any number of ways. In essence, the garden is a large microphone designed to pick up vibrations.
https://folktekarchive.com/instruments/electrocoustic/nanogarden
These merchants probably sell this module. Huh?