Unlike diamagnetic fillers such as carbon, copper, or silver that only shield the electric component of electromagnetic waves, nickel is ferromagnetic and shields the magnetic component as well. It is smooth, hard, and abrasion resistant.
This works well when shielding an electric guitar. It dries fast and is perfect for the old guitar circuits that I love so much but noise is a no-no especially when recording. I am impressed with this product. I used to use a carbon product, but this is far superior in my opinion.