It’s very good items for control CO2 in your apartment. I tested it putting together and they showed the same results. Then I take it off to outside to control decreasing and it’s worked again. Then I blowed through them and it showed the increasing concentration immediately. Generally, I’m satisfied by item’s quality. However, there’re a few weaknesses. It has a weak battery that can keep working for about a couple of hours. But it doesn’t matter if you use it on charge all time as me. Finally, the main disadvantage is the speaker that make a sound when the concentration reaches 1500. The problem is that sound is terrible and loud and you can’t turn it off especially in time while you’re sleeping. After I woke up three time per night to switch this annoying beep off I took it apart and removed the speaker with soldering. Now I’m totally happy.

The device went to Ukraine for a long time 62 days, probably camel. Works from the built-in battery, enough charge for 2 days maximum, charging by yusb type C. The cord is included, there is no block. The temperature shows relatively precisely, running at a maximum of 2 degrees, CO2, it is not clear here, but if you breathe on it, instantly the readings are rising, and the signal is is In general, an interesting thing ....

Delivered in 12 days to Moscow, the track was tracked. The description corresponds, the device arrived charged, turned on after pressing the button. Originally was in the Green Zone, smoothly moved to the yellow, after one and a half hours ran off into the red-how it all works is not clear) you need to get out the device

I bought to measure CO2. It already warned when the CO2 is too high (beeps), but I’m not sure the measurement is reliable since I do not have other instruments to compare. Has an internal battery, but because the leds are always on, it does not last very long.

Works. On average shows 450 ppm, near the stove 550, the most interesting scales at the sink when the water goes. Apparently out of the pipe leaves during the drain and scales up to 2000. Were very surprised by this work of the septic tank at the Cottage)