The tones of this hand tubes consist of the pure overtone series of the Venus tone at 441 Hz. An overtone series is a series of partials that vibrate simultaneously when a natural tone sounds, thus appearing to us as a single tone. Such an overtone series is the purest, absolutely harmonic scale. It was not artificially developed by man, but the pitches result directly from the natural laws of vibration. It follows a universal wave principle of the universe and thus makes it perceptible to us in every respect.