The testo 905i is an air temperature Smart Probe that quickly and accurately measures temperature in rooms, ducts, registers and environmental boxes\/chambers. Users can remotely read the measurements from this or multiple probes by using the testo Smart Probes App installed on their Smart device. Smart Probes can be used individually or in combination with other Smart Probes to create measuring solutions for most HVAC\/R applications. Applications cover setup and diagnostics of large and small HVAC\/R systems.Professional measuring instrument for use with smartphones\/tablets. Measurement of temperatures in rooms, ducts, registers and air outlets. Fast identification of temperature change by graph curve display. Measuring range -50 to +150 °C. Tough, accurate and easy-to-use. Dimensions 222 x 30 x 24 mm. Probe shaft length 100 mmCalibrated = UKASModel Number p = Testo 905i