The Testo 635-1 (0560 6351) Compact Pro Thermo-Hygrometer is for measuring air moisture, material equilibrium moisture, and pressure dew point in compressed air systems. Up to 3 temperature or humidity probes can be displayed; data transmission is radio-controlled, or wireless. Measurement data can be transmitted by infrared to the Testo printer. It is also possible, during cyclical printing, to print measurement data once every minute, for example. The 635-1 furthermore stands out thanks to its intuitive operation and clear menu structure.

The Testo 635-1 immediately displays the dew point difference between ambient air and the wall surface, when analyzing moisture on walls and ceilings. There are precision probes up to -60 degrees C tpd available to inspect pressure dewpoint in compressed air systems.

In addition to measurement with classical probes, a wireless measurement over up to 20 m distance is also possible with the 635-1. This eliminates damage to the cable or difficulties in handling. The wireless probes are available for the measurement parameters temperature and humidity, and up to three wireless probes can be recorded and displayed by the 635-1. The optional plug-in radio module can be retrofitted at any time.