this one in particular is great for emf protection. anyone with enough finess to do reliable and accurate kinesiology can confirm this. if you are trained in the use of a pendulum, you can also test and verify that the location of the energies produced by these shapes are on either side of the shapes which create a rotation (the center is the easiest to measure).
if you would like to train in the actual scientific use of a pendulum (which is called radiesthesia), the biogeometry link has some great references and taking a class if possible would be an amazing adventure for you. worth considering perhaps
i hope this helps you along in your research! best wishes