This CO detector is very nice to look at.
Everything you need to know about what it does is nicely displayed on the 3 inch circular screen.
In a large and brightly lit display it shows you the amount of Carbon Monoxide present as well as
the temperature and humidity of the surrounding area.
Very nice if you are an herpetologists or need to keep your pet tarantula in optimum conditions.
But is what it displays accurate?
The humidity displayed exactly matched the amount shown on my smart thermostat.
According to my trusty thermometer, the temperature was out a tiny bit.
I looked for a method to calibrate it, but sadly this unit does not support that function.
Not that precise temperature accuracy matters much - the detection of Carbon Monoxide is what really counts.
My unit displays ZERO ppm of Carbon Monoxide - which is re-assuring to know.
As this unit is so portable and can be recharged with a regular 5V USB phone charger, I will be taking this with us in our small motorhome travels.
The motorhome has a propane heater, stove and fridge, so an O2 monitor is a must.

What I like about this CEKKIENA Carbon Monoxide Detector:
- The look and feel of it
- The portability and ease of use.
- The display can be changed to always on, or off after ten minutes.
- Color coded light that indicates various degrees of CO detected.. ( green = OK, yellow = 100-200 ppm
red+siren alarm = more than 200ppm)
- Celsius or Fahrenheit display
- 90 hours of use on one charge.

Negatives:
Not really negatives, but this unit cannot be wall-mounted as the USB connector is located on the back of the unit.
There's a flip-out stand at the back of the unit so it can be set on a shelf, counter top, or mantle.
During R.V. travels, it would have to sit in a drawer.

I'm really glad I have this .... some added security for my family - and I'm looking forward to using it in the motorhome..