Shielding Materials - K&J Magnetics
The higher the number, the better the shield. Low carbon steels have a Permeability of 1000 - 3000, while MuMetal can have values as high as 300,000 - 400,000. The saturation point is the flux density at which the material can not contain any more magnetic flux. Steel saturates around 22,000 Gauss, while MuMetal saturates at about 8,000 Gauss.