CCS811 carbon dioxide, air quality sensor mainly uses the CCS811 chip. It is an ultra-low-power miniature digital gas sensor that can detect a wide range of volatile organic compounds (TVOCs), including equivalent carbon dioxide (eCO2) and metal oxide (MOX) levels. Equivalent carbon dioxide (eCO2) is measured in the range of 400 to 29206 ppm (parts per million), and various volatile organic compounds (TVOC) ranges from 0 to 32768ppb(parts per billion). 3mm diameter position hole on sensor contributes to fix on the other device.