Set of 4 magnets 3/4" OD x 1/4" ID x 1/4" thick (19.1 mm x 6.4 mm x 6.4 mm) Material: Neodymium (NdFeB) Grade: N48 Coating: Nickel (Ni) Magnetization: Axial Pull Force: 12.23 pounds SKU# M341414R OD = Outer Diameter ID = Inner Diameter NEODYMIUM MAGNETS ARE NOT SAFE FOR CHILDREN