User Manual
45170 V1.1 5/09 
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Introduction 
Congratulations on your purchase of Extech’s Model 45170 4-in-1 Humidity, 
Temperature, Airflow and Light Meter. With careful use, this meter will provide years of 
reliable service. 
Meter Description 
1.  Vane Airflow Sensor 
2.  Type K Thermocouple Input Jack 
3. Display 
4. Power Button  
5.  Unit /Zero Button 
6. C°/F° /Lux/Ft-cd Button 
7. Light Sensor 
8.  RH and Air Temperature Sensors 
9. Hold Button 
10. Max/Min Button 
11. Function Button 
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