For our family it is very important that we eat, drink, what you breathe, the Windows in the apartment open very often, because the damage from lack of oxygen great.
Decided to buy a device that measures air quality and humidity. Found good store in St. Petersburg, but was confused about the price of about 10 000. Then we decided to look for similar on Aliexpress and found the exact same device 2 times cheaper here on this page.
We ordered it about six months ago for 4500, now the price rose slightly, but for such a device is still very low. Was the detector to us for about three weeks.
Very pleased with the quality, now orientirueshsya on him when it is urgent to ventilate the apartment and turn on the humidifier.
For example, if the air quality does fall, it includes an unpleasant siren, but until then try not to bring it and keep the level of carbon dioxide in normal.
Photo detector 696 is a good result for the dwelling. 400 is the settings on the street, the apartment is good if is 700-800, the alarm device will give 2000 — which means very little oxygen in the air and it is urgent well-ventilated.
Running the detector and battery powered, from the mains, is connected via a usb cable. You can use as a alarm near gas stove or boiler to avoid an explosion of natural gas network or bottled.