The Testo 415-425  

The Testo 415 is an accurate thermal anemometer covering the velocity range from 0 to 10 m/s (0 to 2,000 fpm) and the temperature range from 0 to 50 °C (32 to 120 °F). The Testo 425 covers the range from 0 to 20 m/s (0 to 4,000 fpm) and the temperature range from -20 to 70 °C (-4 to 160 °F). The compact 415 and 425 use a heated wire NTC sensor to measure velocity and temperature for applications in the HVAC industry.
 
Low cost digital thermal anemometer with a wide range of applications:
Measurements on duct outlets
Measurements of air speed in AC ducts
Measurements on exhaust hoods
Clean rooms
Measuring ventilator capacity
 
 
Features:
Multi-point averaging
Time averaging
Parallel temperature measurement
Velocity and temperature values at a glance
Extensive program of accessories
Technical Data Testo 415  Testo 425
Measuring Range 0 to 10 m/s (0 to 2,000 fpm) 

0 to 50ºC (32 to 120ºF) 

 0 to 20 m/s (0 to 4,000 fpm) 

-20 to 70ºC (-4 to 158ºF) 
Accuracy  ±0.05 m/s (0 to 2m/s) [±9.84 fpm (0 to 400 fpm)]; ±0.5 m/s (>2 m/s) [±98.4 fpm (400 to 2,000 fpm) ±0.05 m/s (0 to 2m/s) [±9.84 fpm (0 to 400 fpm)]; ±0.5 m/s (>2 m/s) [±98.4 fpm (400 to 4,000 fpm)
Storage Temperature  -20 to 70ºC (-4 to 158ºF)  -20 to 70ºC (-4 to 158ºF) 
Probe  attached to housing attached to housing by a cable
Warranty  2 years 2 years
Accesories: The Testo TopSafe, protects the thermometer against dirt, dust and shock.