Temtop C1 CO2 Monitor Air Quality Monitor, Indoor Carbon Dioxide Detector, Tester for CO2, Temperature and Humidity

Very good

I'm happy

I have no comparison device in order to verify if it's accurate but it seems like simple and sturdy. I have it since a month in Eco mode and the battery is still at max. The only downside is that the CO2 level arrow isn't gradually moving but only in 3 positions green/yellow/red, the threshold values are simple (1000 and 1500 ppm) and I can live with that.

Perfect little gadget for indoor use

Does what it's supposed to do, without any unnecessary extras. Air quality measurements are reliable, the design is slick and after 2 weeks of using it in different modes the battery is still full. Absolutely satisfied with my purchase, can only recommend.