I used it just a few times.

Info from manufacturer:

The HC-TT is a compact cassette manipulation device which allows you to manually play a cassette with your hands. The resulting sound can be incredibly similar to scratching a vinyl record. Sound will only be produced while your hands are turning either of the large playback knobs. By turning these knobs you are directly rotating the cassette spindles which moves the tape across the internal tape head. The knobs “play” a regular cassette forwards and backwards. There is no motor in this device, so direction and speed is left to the performer. The illuminated touch switch is a momentary mute for both the mono audio output as well as the CV/Gate outputs. The Arches and Moons touch plates allow for feedback and other strange interactions.  This device does not record audio but only outputs pre-recorded audio from any cassette tape.