This application relates to devices in which magnets are arranged so that an intensity of a magnetic field emitted by the magnets is substantially the same at a position of interest for at least two discrete positions of the magnets. The application describes how this can be achieved even when the discrete positions are different distances from the position of interest by identifying locations at which magnetic material can be added to balance the field intensity for both discrete locations. In some embodiments, this type of configuration can be helpful in accommodating movement of magnets between two common positions. When the magnetic field intensity for the position of interest is set near zero a magnetically sensitive component can be positioned at the point of interest with little or no effect from the magnetic field when the magnets are in any of the discrete positions.