This product sends MIDI CC based on the angle of a finger wearing a ring. Almost no one in Japan may know about this product. I believe it was the first or second generation of source audio's "control effects with a ring" series. While other products are listed on the website as legacy products, information about this product has disappeared from the manufacturer's website. However, videos remain on the official manufacturer's YouTube channel. https://www.youtube.com/watch?v=j8Cb5yhaje4 As an example of how to use it, a singer could wear it on their finger, and strings programmed in a PC DAW software would play only when they raise their hand (this is just an example, assuming the settings with the audio interface are correct). A printed English manual is included.