Shielding effectiveness is determined by a combination of the reflection and absorption of RF signals. Absorption depends on the thickness of the shield material. However, reflection occurs at the shield surface and its effectiveness is independent of thickness. Reflection is the determining factor for all high frequency signal attenuation. (Note: When using these materials for conductive shielding gaskets, conductivity is the determinant.) Maximum reflection occurs with the highest conductivity materials – the best being copper, nickel and combinations of both.