Testo 635-2, humidity/temperature measuring instrument with readings memory, PC software and USB data transmission cable, with battery and calibration protocol. The instrument for measuring air moisture, material equilibrium moisture and pressure dewpoint in compressed air systems. Moisture characteristics can be recorded in the instrument memory and analyzed and displayed in graphics or tables. Up to 3 temperature or humidity probes can be displayed in the testo 635-2 meter; data transmission is by radio i.e. wireless. Selectable user profiles, i.e. allocation of specific function buttons and menu-guide to an application enable intuitive operation. Material moisture can be displayed immediately on account of the special probe. Characteristics for different materials can be stored in ComSoft and transmitted to the instrument. testo 635 immediately displays the dewpoint difference between ambient air and the wall surface in the analysis of moisture on walls and ceilings. Precision probes up to -76degree F tpd are available to check pressure dewpoint in compressed air systems. The humidity sensor developed by Testo has proven itself worldwide and has outstanding features in terms of precision, long-term stability, temperature resistance and robustness. Direct display of material moisture due to freely settable characteristics curves (based on equilibrium humidity). Storage of single measurements or measurement series by measurement location. Instrument memory for up to 10,000 readings. Protection class IP54. U-value probe connection option. Storage temperature: -22 to +158 degree F. Operating temperature: -4 to +122 degree F. Battery type: Alkali manganese, mignon, Type AA. Battery life: 200 hr (without radio operation). Material/Housing: ABS/TPE/metal. Measures 2-29/32" length by 1-103/128" width by 8-21/32" height.