Many physics experiments, such as neutron or electron electric dipole moment measurements, require operation in a null or stable magnetic field, for which a combination of active and passive shielding is usually required. Our fluxgate sensors are ideal for providing feedback in active cancellation. Typically, one-part or two-part Mag-13MS or Mag-13U-TPU sensors, alongside the Mag-03IE or Mag-03MCTP can be used. Two-part construction enables placement of the sensor head in a confined space, with the electronics placed further away. The Mag690 is an alternative sensor. For cryogenic applications, CryoMag or the single-axis Mag-01H and Mag F Probe may be preferred. The same methods may also be used to shield interference from sensitive equipment, such as an electron microscope.