For refrigeration engineers: The kit contains two testo 549i high-pressure gauges, two testo 605i thermohygrometers and two testo 115i clamp thermometers. Used in conjunction with your smartphone/tablet, the kit is ideal for servicing, troubleshooting and installing air conditioning and refrigeration systems. The testo Smart Probes App makes your work easier and more efficient: over 90 stored refrigerants, automatic calculation of superheating/subcooling, target superheat and cooling/heating power, emailing of measurement data reports as PDF or Excel files.