This part of ISO 15548 identifies the functional characteristics of a probe and its interconnecting elements and provides methods for their measurement and verification. The evaluation of these characteristics permits a well-defined description and comparability of eddy current equipment. By careful choice of the characteristics, a consistent and effective eddy current examination system can be designed for a specific application. Where accessories are used, these should be characterised using the principles of this part of ISO 15548. This part of ISO 15548 does not give the extent of verification nor acceptance criteria for the characteristics. These are given in the application documents.