Temperature measuring instrument testo 922. designation: Differential temperature measuring instrument for thermocouple type K. Display: digital. Multiple display. Measuring range: -50 to 1000 °C. The testo 922 is a compact differential temperature measuring instrument which is highly valued in industry and trade. It determines temperatures quickly and precisely and calculates the differential temperature directly in a large measuring range from -50 °C to 1000 °C. Documentation is easy via the practical testo Smart App for smartphones and tablets. A typical application is checking the flow and return temperatures on heating circuit manifolds. Two type K thermocouple probes are included in the scope of delivery, but the testo 922 is also compatible with other commercially available type K thermocouple probes. The testo Smart App not only supports the documentation of the measurement results, but also the configuration of the testo 922 as well as the display and storage of the measurement values. Particularly practical: the app transforms your smartphone into a second display.