Take care not to over tighten the screw to prevent breaking the magnet material. Ferrite Countersunk Shallow Pot Magnet. The Eclipse ferrite countersunk shallow pot magnets are an excellent solution for many of your applications. The magnet is a ferromagnetic steel cup with a countersunk ring magnet inserted. Features and Benefits. For clamping and holding applications 120° maximum operating temperature Excellent resistance to corrosion Mild steel pot with zinc plated body