It is also known as The Golden Ratio, Phi, and The Divine Proportion.
These beautiful calipers can be used in the design process to measure and check if distances between design components are Golden Mean, and then adjust them accordingly to fit the ratio.
As nature constructs predominantly grow and create themselves using this ratio, if used in ones designs, it has the effect of making the design look more organic and naturally pleasing to the eye.
These calipers are available in the tools section of my website:
https://jeanburgers.com/collections/tools