"Halbach arrays now have many applications and are used in a range of systems of varying complexity. One of the simplest applications of Halbach arrays is in refrigerator magnets. In this case the one-sided flux properties are exploited in order to boost the holding power of the magnet. Variable arrays of magnetics rods can also be combined to create simple locking systems. If the magnetizations of the rods are arranged so the field is maximised above the plane and minimised below it, the flux confinement can be flipped by rotating each rod 90 o."