It's like Auto Tune for the Theremin. This theremin plays notes auto-tuned in the scale or mode of your choice. Great for musical beginners. You can easily play melodies and improvise in key, or just make spooky horror movie sounds. The notes slide like a theremin, but stop on a correct note in the right scale. You can choose the scale and select an "overtone" second voice for the theremin as well. This autotuning makes it easier to play and gives more control than even a Tannerin/Electro-Theremin.