In order to achieve precisely accurate measurements of residual magnetism it is necessary to minimize the effect of the earth's magnetic field. Maurer Magnetics Mini-Zero-Gauss-Chamber is designed to shield the probe from not just the earth's magnetic field but also the magnetic field of your local environment (rebar, steel structures, machinery, etc).
Once the probe is zeroed you can easily measure the additive effect of your environment and deduct the value from measurements made of your parts. Please note that it is important to observe the direction of the probe and part when taking measurements and making corrections. A full-size, desktop version is also available. The Mini-Zero-Gauss-Chamber is suitable for all M-Test devices.