Ambient Field

The magnetic field already present where an accessory is tested, with the PEMF device switched off. It comes from the Earth's field and from electrical equipment nearby, and it can shift a little as the room changes over a long test. Gauss Labs reads the ambient field at the start of every test and again at the end, with the device off and the probe where the accessory sits. Those two readings let the analysis account for the room's own field, so the measurements reported for the device are more accurate. The report gives both readings in gauss. See Gauss Meter.