Eddy current testers are non-destructive testing devices used to detect surface and near-surface flaws in conductive materials. They work by generating an alternating magnetic field, which induces circulating currents, known as eddy currents, in the material. Variations in these currents can indicate the presence of defects such as cracks or corrosion. These testers are commonly used in industries like aerospace, automotive, and manufacturing to ensure the integrity of components. They are valued for their speed and accuracy, allowing for quick inspections without damaging the tested materials. Eddy current testing is also effective for measuring material thickness and conductivity.