REED SD-9901 SD Series Indoor Air Quality Meter, Datalogger (O2, CO2, CO, Temp/RH)


This indoor air quality (IAQ) datalogger measures Oxygen, Carbon Dioxide, Carbon Monoxide, Temperature and Humidity. The SD-9901 is capable of recording readings from 3 probes simultaneously and displays measurements on a large backlit LCD. Using a SD card (max 16Gb), a user can select a desired sampling rate and quickly generate an Excel file on a SD card without the use of software. Optional accessories include a tripod and AC adapter for continuous long-term monitoring. Optional PC software also allows a user to track live measurements.


  • Measures oxygen (O2), carbon dioxide (CO2), carbon monoxide(CO), temperature and humidity
  • Records up to 3 readings simultaneously
  • User adjustable audible alarms
  • User selectable unit of measure (°F or °C)
  • Data hold and Max/Min functions
  • Real-time datalogger with integral SD memory card
  • User selectable sampling rate from 2 secs to 8 hrs
  • Large, easy-to-read backlit LCD display
  • Optional PC software features live tracking via USB connection
  • Tripod mount for long-term monitoring
  • Low battery indicator and auto shut off


Measuring Ranges32 to 122.0°F (0 to 50.0°C)
Dew Point: -13.5 to 120.1°F (-25.3 to 48.9°C)
Wet Bulb: -6.9 to 122.1°F (-21.6 to 50°C) 
Accuracy±1.5°F (±0.8°C)
Measuring Range5 - 95% RH
Accuracy>70%RH: ±(3% rdg + 1%RH)
<70%RH: ±3%RH
Resolution0.1% RH
Measuring Range0 to 4,000 ppm
Accuracy< 999 ppm: ±40 ppm
>1,000 ppm: ±5% Rdg 
Resolution1 ppm
Measuring Range0 to 1,000 ppm
Accuracy±(5% + 2 ppm)
Resolution1 ppm
Measuring Range0 - 30% O2
Accuracy±(1% + 0.2% O2)
General Specifications
Alarm Threshold<18% O2
Response Time1 sec
Display4-digit dual LCD
Backlit DisplayYes
Data HoldYes
Datalogging CapabilitiesYes
Real-Time Clock and Date StampYes
Selectable Sampling RateYes (2secs to 8hrs)
External MemoryYes, expandable up to 16Gb with SD card (optional)
Auto Shut-offYes (after 10 mins/off)
Kick StandYes
Tripod MountableYes
Low Battery IndicatorYes
Power Supply6 x AA batteries or AC Adapter (optional)
PC ConnectivityUSB Cable (optional)
Software  SW-U801-WIN Software (optional)
Software OS CompatibilityWindows XP / Vista / 7
Product CertificationsCE
Operating Temperature0 to 122°F (0 to 50°C)
Storage Temperature14 to 140°F (-10 to 60°C)
Operating Humidity Range10-85%
DimensionsInstrument: 7.0 x 2.7 x 1.8" (177 x 68 x 45 mm)
Humidity Probe Length: 7.8" (197 mm)
CO Probe Length: 5.9" (150 mm)
CO2 Probe Length: 7.5" (190 mm)
O2 Probe Length: 5.9" (150mm)
Weight0.8lb (350g)