Anti-magnetic refers to the property of a watch or its components to resist the effects of magnetic fields. In watchmaking, this is crucial because magnetic fields can disrupt the accuracy and functionality of a watch's movement. Traditional mechanical watches are particularly susceptible to magnetism, which can cause the metal components within the movement to become magnetized, leading to erratic timekeeping or complete stoppage.

To combat this, watchmakers employ various techniques and materials. One common approach is the use of non-ferrous materials, such as silicon or alloys like Nivachron, in the construction of critical components like the balance spring. These materials are inherently resistant to magnetism, ensuring that the watch maintains its accuracy even when exposed to magnetic fields.

Additionally, some watches are designed with protective inner cases or shields made from soft iron, which create a Faraday cage around the movement. This cage effectively diverts magnetic fields away from the movement, preserving its precision.

The importance of anti-magnetic properties has grown with the increasing presence of magnetic fields in everyday life, from electronic devices to magnetic clasps. As a result, many modern watches are tested and certified to withstand specific levels of magnetic exposure, ensuring reliable performance in various environments.