The Graphtec ISO-17025-260 ISO-17025 Calibration is for use with the Graphtec GL260 Datalogger. A recommended annual calibration is vital in ensuring precise measurement and traceability. The ISO/IEC 17025 is the international reference for testing and calibration laboratories wanting to demonstrate their capacity to deliver reliable results. It is also useful for universities, research centers, governments, regulators, and other conformity assessment bodies that need to do testing, sampling, or calibration.