Consisting of RoHS-compliant shielded magnetic assembly with rubber jacket, GN 51.6 Steel Retaining Magnet Assemblies, Disc-Shaped, with Two Internal Threads and Rubber Jacket come in metric sizes and suit applications where surface is readily marred. Magnets' coefficient of friction lends to maximum lateral retaining force. While magnet housing is of zinc plated steel, magnet is neodymium, iron, and boron (NdFeB), and rubber jacket is black elastomer (TPE) 73 shore.