Technical Manufacturing Corp. (TMC) is offering a dynamic, continuously monitoring magnetic field cancellation system that compensates for the interference that affects the performance of scanning and transmission electron microscopes, electron beam lithography systems and focused ion-beam instruments. The open cube-shaped Mag-NetX compensates for fluctuations caused by nearby machinery, elevators and power lines. It detects magnetic fields and sends out an equal and opposite field to cancel the interference. Comprising a dedicated controller with automated calibration and self-test features, an AC and DC magnetic sensor, and Helmholtz coils in a structural casing, the system can be floor-, wall or tool-mounted and sized to user specifications. It achieves attenuation of 35 to 40 dB.