Neodymium clamping magnets are made of a powerful Neodymium magnet sunken into a steel shell, meaning that the north pole is on the center of the magnetic face and the south pole is on the outer edge around it. These eyebolts are machine lathed. The steel pot increases the adhesive force of the magnets, giving them an incredible hold for their size. An added advantage of these magnets is that they are resistant to chipping or cracking following constant impact with a steel surface. IDEAL FOR MAGNET FISHING. Perfect for salvaging various ferrous materials such as coins, safes, nails, bikes, and more, this magnet is ideal for your next magnet fishing trip. Also, this lifting magnet is a great choice for lifting, hanging, and retrieving. STEEL SHELL CASING. Neodymium pot magnets are made of a powerful Neodymium magnet sunken into a steel shell that increases the adhesive force of the magnets, giving them an incredible hold for their size. RESISTANT TO CRACKING & CHIPPING. An advantage of pot magnets is that they are resistant to chipping or cracking following constant impact with a steel surface. STRONG MAGNETIC HOLD. Each magnet can support 13.6kg vertically from the magnetic face when in flush contact with a mild steel surface of equal thickness. SPECIFICATIONS. 20mm diameter x 34mm tall with a M4 eyebolt. M4 threaded collar for assembly.