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Reed R9900 Indoor Air Quality Meter


The Reed R9900 Indoor Air Quality Meter simultaneously monitors carbon dioxide, relative humidity, and temperature. The R9900 is capable of automatically calculating wet bulb and dew point temperatures as well as statistical TWA and STEL averages.

  • Triple LCD display simultaneously monitors carbon dioxide (CO2), relative humidity and temperature
  • Automatically calculates dew point and wet bulb
  • Calculates statistical weighted averages of TWA (8 hour time weighted average) and STEL (15 minute short term exposure limit)
  • User adjustable audible alarm
  • Data hold, Max/Min and average functions
  • Low battery indicator and auto shut off
  • Includes batteries and hard carrying case
Part Number: R9900
Attribute nameAttribute value


Temperature Range :-10 to 60°C (14 to 140°F)
Temperature Resolution :0.1°C/°F
Temperature Accuracy :±0.6°C (±0.9°F)
Humidity Range :0 to 99.9% RH
Humidity Resolution :0.1% RH
Humidity Accuracy :±3% (10 to 90% RH); ±5% (<10% & >90% RH)
CO₂ Range :0 to 5,000 ppm
CO₂ Resolution :1 ppm
CO₂ Accuracy :< 999 ppm: ±40 ppm; >1,000 ppm: ±5% Reading
Dimensions LxWxH :200 x 70 x 57 mm (7.9" x 2.7" x 2.3")
Weight :190g (6.7 oz)