An EMF neutralizer doesn't eliminate EMF waves. Instead, it equalizes them and makes them more regular, or “coherent”. To understand how this works, think of a pair of noise cancelling headphones. They don't have some magical way of literally blocking out all noise.

Does EMF jewelry really work?

This is a tough answer because there are so many different emf protection jewelry products on the market, using completely different technologies and concepts to protect against EMF radiation. So the short answer would be Yes, they absolutely can work, but there are many fake products on the market.

What material can block EMF?

Typical materials used for electromagnetic shielding include sheet metal, metal screen, and metal foam. Common sheet metals for shielding include copper, brass, nickel, silver, steel, and tin.