Klein Tools ET110 CO Meter, Carbon Monoxide Tester and Detector with Exposure Limit Alarm, 4 x AAA Batteries and Carry Pouch Included
$139.99
Price: $139.99
(as of Dec 14, 2025 11:19:48 UTC – Details)
The ET110 CO Detector is an easy-to-use meter that detects and measures concentration levels of carbon monoxide (ppm) and temperature (Fahrenheit/Celsius), making it the perfect choice for HVAC professionals. Features backlit LCD screen, warning indicator light, audible and visual alarms and multiple function buttons. Includes carrying pouch and 4xAAA batteries. For more than 160 years, Klein Tools has manufactured premium-quality, professional-grade hand tools that deliver the performance, durability and precision needed to get the job done right. Our family of engineers, workers and craftsman continue to put six generations of expertise into every tool we create by using only the highest quality materials, superior workmanship, and keeping manufacturing as close to home as we can. Klein isn’t just the name of our company, it’s also our family name. And since we’re an American company that’s family-owned and family-run, you know you can count on us to be here tomorrow. Klein Tools doesn’t just make great products, we make great products that stand up to the demands of the professionals who use them every day … Since 1857.
ACCURATE CO GAS MEASUREMENT: Detect and measure carbon monoxide gas levels with precision using our easy-to-use CO meter
PORTABLE AND PROTECTIVE: Carry our CO detector anywhere for user safety, with a built-in short-term exposure limit (STEL) alarm
DUAL ALARM SYSTEM: Stay informed about CO levels with both low (35 ppm) and high (200 ppm) level alarms, ensuring prompt action
AUDIBLE AND VISUAL ALERTS: Receive immediate warnings through audible and visual alarms, providing increased safety and peace of mind
CLEAR DISPLAY: Backlit display shows CO measurements (0 to 1000 ppm) and temperature (Fahrenheit and Celsius) for easy reading
BATTERY SAVING FEATURE: Auto-power off after 20 minutes of inactivity helps conserve battery life, extending the device’s usability
CONVENIENT PACKAGE: Includes a carrying pouch and 4xAAA batteries, making it easy to transport and operate the CO meter efficiently
Customers say
Customers find the carbon monoxide meter reliable, noting it has saved lives, and appreciate its quality and ease of use. They consider it a great value and essential for safety, with one customer mentioning it’s particularly useful during winter. The accuracy receives mixed feedback, with some customers reporting accurate CO measurements while others experience inconsistent readings. The readout time is also mixed, with several customers noting a 20-second delay. Battery life is a concern, with one customer reporting issues with discharged batteries.
11 reviews for Klein Tools ET110 CO Meter, Carbon Monoxide Tester and Detector with Exposure Limit Alarm, 4 x AAA Batteries and Carry Pouch Included
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Kelle_Jane –
Appears to work as expected.
Appears to work as expected.Reports zero when in clear air.Reports over 300PPM when placed about 4ft from UTV exhaust (it’s a 20 year old gas engine).The response time was 2-3 seconds 4ft from gas engine exhaust and readings zoomed over 300ppm and I moved away. Real world quick test appears to work.I tested our home air ducts in several places with this meter and all of them read 0.We wanted to put a number to CO ppm in addition to the smoke detectors with CO detection which always show OK without any numeric value. Having a good quality meter seems like a wise idea if you have natural gas or propane heating. I am happy with the unit after one use.Note: If you are a home owner and not likely to use the meter very often, consider removing the AAA batteries after each use so there is no chance of a battery leaking into the meter.
Tim –
great tool, alerts us of CO before the alarm can go off!
I bought this because we have had 2 CO alarms go off at like 10PM, which is no fun. Yup fire dept and local natural gas tech had to show and clear our house of CO leaks, BEFORE we could get back in our house.Turns out our gas fireplace had glass chips in it – something great new idea apparently – but they we covering up the air slots in the interior of the gas fireplace. So the CO was being kept down inside the fireplace, instead of pulling in the fresh air from the house.Once I removed the glass chips it did fix the problem!!! But I wanted to be sure and not get the opportunity to be stuck outside again! Thanks to a local fireplace install company!I kept the Klein CO sensor running for a couple of hours and no CO!!!
Virginia Customer –
Finally a good CO monitor
I bought this after buying four cheesy units that were advertised (@ $55) for home CO monitoring. The other units came with poor instructions, worse execution and constantly gave false alarms. This unit by Klein tools is built solid, instructions were simple, clear and easy to use and the unit gave rapid and accurate readings. Excellent
Dick Turpin –
Affordable Meter – Still have anxiety
Overall, I like this item and it seems to give reliable readings. But the accuracy is questionable at times, as some other reviews have noted.First, there definitely seems to be about a 20 second delay at all times. I can walk behind my running car with the device, and roughly 15-20 seconds later, the readings clearly jump to 20-40 ppm. Walking into a clean space seems to be a quicker response. Often less than 10 seconds.I have had a couple odd moments where my parking garage registers zero ppm. This would be impossible.I’ve come to the odd conclusion with this device that parking lots have terrible air, even though they’re outdoors. Walking through a busy mall parking lot, I got a jump to 50ppm on this device, but in my ENCLOSED parking garage, I’ve never once seen a reading above 20ppm. Thank goodness for HVAC I guess.I’ve also seen a few odd moments where the clean air in my home will jump from 0ppm to 3ppm and instantly back down to 0. I wonder what this means. Just a possible “waft” of CO?I’d also recommend that the engineers who developed this device consider de-coupling the Max/Average clear button. Just because I want to clear the Max doesn’t mean I want to clear my Average. Does that make sense?
Marnie Gordon –
Sensitive, easy to use, CO2 tester
I had several propane leaks in a new house that we moved into. I bought the gas sniffer from Klein which was great. At that point I wanted to make sure nothing else was wrong. So I bought this. To test it I tried it in another house that had a ventless propane fireplace. Once i turned the fireplace on it registered a slight increase in CO2, but well within an acceptable range. It brought peace of mind to my wife which makes it priceless!
J W R –
Klein tool works well
Klein tools work as they should.
Michael Earle –
Bought this to get rid of my fears
I was feeling sick and couldn’t figure out why, so I brought back out my air quality tester (that is now in the garbage), and it signaled to me that the CO was extremely high in my room, scared the crap out of me, got this overnighted to me, turns out the cheap Chinese air quality tester has a tendency to be completely WRONG. Keeping it around in a drawer for future use, but this thing is awesome, well built and seemingly very accurate.
Placeholder –
Good value.
Testo has become my brand of choice for HVAC.
Nicholas –
Easy to use quality Meter
Nicolas C. –
Una opción muy económica para los que usan en mina, funcional pero muy grandes
Kyle Stallard –
Great product! Fast delivery… Thanks 🙂