The Testo 0613 5507 Set of Temperature Clamp Probes is designed for measuring the surface temperature of pipes (diameters from 0.2 to 1.4 in.) and offers numerous application options. For example, the probes are ideal for measuring flow and return temperatures on heating systems and can also be used for detecting superheating/subcooling on refrigeration systems. The fixed cable is used to connect the clamp probe to a measuring instrument, such as a digital manifold (sold separately). The clamp probe is equipped with a high-quality NTC sensor and features a high measuring accuracy of ±1.8 °F (-4 to 185 °F).