Below is a list of Mu Metal® manufacturers from Butler, Wisconsin. Mu Metal is a nickel-iron alloy that is used to protect sensitive devices from magnetic fields that would cause magnetic interference. Mu Metal consists of 80% nickel, 15% iron and a small amount of molybdenum. This composition allows for high magnetic permeability, low coercive force, low remanence, which makes mu metal valuable in magnetic shielding applications.