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Gain Express

Portable CO2 Meter Handheld CO2 Detector Monitor 0~9999ppm, Carbon Dioxide Meter with Alarm Function, Temperature & Humidity Meter NDIR Sensor Air Quality Monitor for Home Trip Classroom and Office

  • Based on 299 reviews
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Availability: In Stock.
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Arrives Thursday, Oct 22
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Features

  • HIGH ACCURACY: CO2 Accuracy 0~2000ppm(50ppm or 5% of the reading); 2000~9999ppm(10% of the reading)
  • LARGE MEASURING RANGE: CO2: 0~9999ppm ; Temperature: -10~60C(Accuracy 0.6C) ; Humidity: 0.1% ~ 99.9%RH(Accuracy 3%RH) ; Dew Point: -20.0~59.9C ; Wet Bulb: -5.0~59.9C
  • USER FRIENDLY: Portable Handle Design; Easily manual calibration on CO2 and humidity; Stable NDIR CO2 sensor
  • POWER SUPPLY: Dual power source battery (included) or 9V adaptor (NOTED: adaptor is not included in set); Power from battery is automatically cut off when 9V adaptor is in use
  • APPLICATION: IAQ monitoring and survey; especially on CO2 level and air ventilation become widely applied in public areas such as offices; classrooms; factories; hospitals and hotels

Description

We are a high-tech enterprise offering independent development, design, production, and sales of top-quality instrumentation globally Gain Express is a manufacturing and trading company that researches and produces high-tech & high-quality products, and offers a wide range of electronic products & testing instruments. Gain Express has years of trading experience (B2B & B2C) with many customers from North America, South America, Asia, Australia/Oceania, Europe, Africa, the Middle East and so on. Ideal for maintaining and monitoring indoor air quality in diverse settings such as homes, offices, schools, and other environments

Brand: Gain Express


Style: Digital CO2 Meter


Power Source: Battery Powered


Color: Yellow


Item Weight: 200 g


Alarm: Audible


Operating Humidity: 99 9 percent


Upper Temperature Rating: 60 °C


Unit Count: 1 Count


Manufacturer: Gain Express Holdings Ltd


Brand: Gain Express


Model Number: A017755


Unit Count: 1 Count


Manufacturer: Gain Express Holdings Ltd


UPC: 600316560665


Mfr Part Number: A017755


Power Source: Battery Powered


Alarm: Audible


Operating Humidity: 99 9 percent


Upper Temperature Rating: 60 °C


Product Style: Digital CO2 Meter


Color: Yellow


Item Weight: 200 g


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Oct 22

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

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Top Amazon Reviews

    • Fairly simple to use.
Works great. We use it to monitor corn in our grain bins.
Reviewed in the United States on September 2, 2026 by John Henry
    • Good quality and durable
We've bought several of these over the years and they are workhorses. Alway work, battery lasts forever, accurate and consistent.
Reviewed in the United States on August 24, 2024 by Coquelicot
    • Adjust the readings for altitude, calibrating it outside may not work
Review Image by Larry
Review Image by Larry
From the SPECIFICATION, the CO2 readings must be increased by 1.6% for each kPa below normal pressure (101.33 kPa). At an altitude of 1000 feet (above sea level) the pressure is 97.717 kPa so the readings must be multiplied by 1.0578 101.33 – 97.717 = 3.613 3.613 x 1.6 = 5.78 The meter instructions say regularly calibrate it and they say it can be calibrated outside in well ventilated sunny weather. But, an accurate calibration outside probably isn’t possible. The meter instructions say it can be calibrated outside but it also says the CO2 concentration must be 400 ppm where the calibration occurs. The calibration instructions don’t mention that the calibration would need to be done at sea level and they don’t mention 400 ppm probably doesn’t occur at sea level in the northern hemisphere. If 400 ppm occurred at sea level and if the calibration was done at 1000 feet altitude, then an error of 5.78% would occur in the meter after the calibration. The lowest dry mole fraction of CO2 in the northern hemisphere may be at a remote location like Mauna Loa. 420.85 ppm CO2 was the Daily Average dry mole fraction at Mauna Loa February 24 2022. It can be 500 ppm in a city like New York. Mauna Loa is the only place I could find with daily CO2 measurements. The last time it was 400 ppm at Mauna Loa was around 2015. The dry mole fraction doesn’t vary with altitude but the concentration does vary with altitude (from “How we measure background CO2 levels on Mauna Loa”). So, the meter must be measuring the concentration since the readings must be adjusted if it isn’t used at sea level. ... show more
Reviewed in the United States on February 25, 2022 by Larry
    • Portable CO2 Meter Handheld CO2 Detector Monitor 0~9999ppm
Portable CO2 Meter Handheld CO2 Detector Monitor 0~9999ppm Product arrived quickly and was brand new. I put in the 4 batteries and hit the top left start button, and it fired right up. This CO2 detector is a game changer. I thought the office had a Carbon Monoxide problem. After buying a expensive CO detector [everyone should have a CO detector of some type] I found out with this device it was CO2 that was the problem. The room was running at 800 ppm to 900 ppm and thats when a absolute brain fog would hit. We ended opening up some windows limiting the use of the gas stove and brought in fans for circulation. The PPM is now about 500 ppm sometimes around 430 ppm which is a huge difference. I have not messed with any of the setting so far no need to. Overall excellent product! If you are having a brain fog or feel a little strange and lethargic in the house/room or office it may be high CO2 levels. This device will help determine if that is the issue, and hopefully help you solve it. ... show more
Reviewed in the United States on March 27, 2026 by Supersport-68
    • Quirky late 1980’s design aesthetic but it works
Indispensable instrument in this time of pandemic to ensure that your environment is adequately ventilated. I’m glad I bought this; my tightly sealed house had a reading of 1600 PPM CO2 and this meter clearly shows when the windows have been opened long enough to bring CO2 down to a healthier level of 600 to 800 ppm. Buy this if you want to look like a contractor. It’s ginormous and yelliw but actually light weight, especially for the size. C02 reading comes up in 30 seconds after a countdown; initial indoor relative humidity indoors after unit is outdoors takes a while to stabilize maybe ten or 15 minutes. The toggle between air, wet bulb, and dew point temperature is nice; kind of wish it also showed heat index. Now the bad: Terrible human factors design; without the manual you’d never figure this thing out - fortunately the tiny manual explains it all pretty well. Don’t lose the manual. Buttons are excessively debounced to the point that sometimes a button press isn’t recognized. A RS232 interface??? Stone age technology and forget about using your phone to log data. Alarm initially set to 1000 PPM probably isn’t a good choice; if you take this to your local grocery store or neighborhood bar or school or workplace and make a measurement that’s above this strict limit you’ll freak everyone out. It’s easily changed (but don’t forget the manual) I would buy this again. It works well. I like it. ... show more
Reviewed in the United States on August 15, 2020 by Jackalope
    • Accurate
The instruction booklet is small, so it’s hard to read. The measurements are straightforward and easy to read. I bought this to test air quality in my house for Covid reasons.
Reviewed in the United States on January 3, 2021 by Indie music fan
    • Instructions?? User interface??
Difficult setup. Manual is completely useless.
Reviewed in the United States on August 3, 2026 by Amazon Customer
    • Professional monitor for measuring carbon dioxide level!
I am using it in my work station and it gave me accurate readings. I have used different CO2 testers before and this one is the best one so far. It is easy to use and user-friendly. I tried some of the cheap CO2 testers in the past and I feel much more confident with this new tester. It's well worth the money and I strongly recommend it. ... show more
Reviewed in the United States on October 22, 2019 by David

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