Magnetic fields permeate most materials!A magnetic field will effortlessly pass through any non-ferrous material"Ferrous" means relating to, or containing, iron.This means that the field will remain unaffected... even if the magnet were encased by a barrier made of wood, lead, plastic, etc!However the field is affected in the presence of a ferrous metal. Ferrous metals warp the magnetic field.You can't technically "block" the field off, but you can "bend" it away!You can't stop a magnetic field dead in its tracks, but you can manipulate and distort it!In many cases this is as good as "shielding" the magnetic field!In the diagram below, a magnetic field is shown in conjuction with a piece of steel.The magnetism doesn't stop when it runs into the steel, but instead runs along that ferrous metal as if it were an extension of the magnet itself!If the steel is thick enough (as shown), the magnetic field will be so distorted that it will not be felt on the opposite side of the metal!To bend the field away:If you select the side of a magnet that you don't want to magnetic field, you could encapsulate or cover here with thick steel or other ferrous metal. This will push some or all of the magnetic field out sideways, along the surface of the metal.We stock a range of Ferrite and Rare Earth magnets that are capped in metal holding pots which results in a diminished field on the covered side.We also carry a small range of single-sided Ferrite disc magnets.