| 971 | 922 | 975 (975V) | 985 | CO-220 |
| Record storage | 99 | 99 | 25,000 records (continuous), 99 records (discrete) | 10,000 | |
| Downloadable data | | | | USB or Ethernet | |
| Battery type | (4) AAA | (4) AA | Rechargeable Li-Ion (primary),
(3) AA (backup) | Rechargeable Li-Ion 7 .4 V 2600 mAh | (1) 9V |
| Warranty | 2 years | 2 years | 2 years | 1 year | 1 year |
| Indoor air diagnostic applications | | | | | |
| Air velocity | | | | | |
| Air pressure | | | | | |
| Air flow (volume) | | | | | |
| Carbon dioxide | | | | | |
| Carbon monoxide | | | | | |
| Temperature | | | | | |
| Humidity | | | | | |
| Dew point/wet bulb | | | | | |
| Particle concentration counting | | | | | |
| Air pressure/air velocity/air flow | | | | | |
| Air pressure range | | ± 4000 Pascals
| | | |
| | ± 16 in H2O | | | |
| | ± 400 mm H2O | | | |
| | ± 40 mbar | | | |
| | ± 0.6 PSI | | | |
| Air pressure accuracy | | ± 1 % + 1 Pascal
| | | |
| | ± 1 % + 0.01 in H2O | | | |
| | ± 1 % + 0.1 mm H2O | | | |
| | ± 1 % + 0.01 mbar | | | |
| | ± 1 % + 0.0001 PSI | | | |
| Air velocity range | | 250 to 16,000 fpm/1 to 80 m/s | 50 .0 fpm to 3000 fpm/0 .25 m/s to 15 m/s | | |
| Air velocity accuracy | | ± 2 .5 % of reading at 2000 fpm (10 .00 m/s) | ± 4 .0 % of reading above 50 fpm (0 .25 m/s) | | |
| Air flow (volume) range | | 0 to 99,999 cfm | | | |
| Air flow (volume) accuracy | | Accuracy is a function of velocity and duct size | | | |
| Temperature relative humidity | | | | | |
| Temperature range | -20 °C to 60 °C (-4 °F to 140 °F) | 0 °C to 50 °C (32 °F to 122 °F) | -20 °C to 50 °C (-5 °F to 122 °F) | | |
| Temperature accuracy | 0 °C to 45 °C (± 0 .5 °C)/-20 °C to
0 °C and 45 °C to 60 °C (± 1 .0 °C) | 0 °C to 50 °C (± .01 °C) | 40 °C to 60 °C (± 0 .9 °C)/5 °C to
40 °C (± 0 .5 °C)/-20 °C to
5 °C (± 1 .1 °C)
| | |
| 32 °F to 113 °F (± 1 .0 °F)/-4 °F
to 32 °F and 113 °F to 140 °F (± 2 .0 °F) | 32 °F to 122 °F (± .01 °F) | 114 °F to 140 °F (± 1 .6 °F)/
40 °F to 113 °F (± 1 .0 °F)/-5 °F to 113 °F (± 1 .98 °F) | | |
| Relative humidity range | 5 % to 95 % RH | 0 % to 90 % RH | 10 % to 90 % RH | | |
| Relative humidity accuracy | 10 % to 90 % RH @ 23 °C (73 .4 °F) (± 2 .5 % RH)
| 0 % to 90 % RH @ 23 °C (73 .4 °F) (± 2 .0 % RH) | 10 % to 90 % RH @ 23 °C (73 .4 °F) (± 2 .0 % RH) | | |
| < 10 %, > 90 % RH @ 23 °C (73 .4 °F) (± 5 .0 % RH) | | | | |
| Carbon dioxide/carbon monoxide | | | | | |
| Carbon dioxide range | | | 0 to 5000 ppm | | |
| Carbon dioxide accuracy | | | 2 .75 % + 75 ppm | | |
| Carbon monoxide range | | | 0 to 500 ppm | | 0 to 1000
ppm |
| Carbon monoxide accuracy | | | ± 5 % or ± 3 ppm, whichever is greater,
@ 20 °C (68 °F) and 50 % RH | | 5 % or ± 2 PPM |
| Particle counting | | | | | |
| Flow rate | | | | 2 .83 L/min (0 .1 cfm) | |
| Particle size range | | | | 0 .3 µm - 10 .0 µm (6 channel) | |
| Cound modes | | | | Raw counts, #/m3, #/ft3, #/liter in Cumulative or Differential mode | |
| Counting efficiency | | | | 50 % @ 0 .3 μm; 100 % for particles > 0 .45 μm (per ISO 21501) | |
| Concentration limits | | | | 10 % at 4,000,000 particles per ft3 (per ISO 21501) | |