In 1978, the Swiss music researcher Hans Cousto determined the tones of planetary cycles by means of the Cosmic Octave and had the first tuning forks made with the corresponding frequencies.
Tuning fork models
The tuning forks are available in four models: S, Plus, L and Lplus.
Size comparison of tuning forks with 136.10 Hz
Tuning forks with higher frequencies are shorter in each case.