Radio frequency (RF) shielding is required when it is necessary to block high frequency 100kHz and above interference fields. These shields typically use copper, aluminium, galvanised steel, or conductive rubber, plastic or paints. These materials work at high frequencies by means of their high conductivity, and little or no magnetic permeability. Magnetic shields use their high permeability to attract magnetic fields and divert the magnetic energy through themselves. With proper construction, magnetic shielding alloys have the ability to function as broadband shields, shielding both RF and magnetic interference fields.