> For the complete documentation index, see [llms.txt](https://sensorbeeab.gitbook.io/sensorbeeab-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sensorbeeab.gitbook.io/sensorbeeab-docs/readme/sensorbee-air-product-manual/sensorbee-air-pro-2/quick-start-guide/5.-accessories-of-air-pro-2-cellular/5.1-internal-add-on-sensors.md).

# 5.1 Internal add-on Sensors

The Sensorbee Air Pro 2 Cellular unit is capable of housing up to six internal gas sensors (e.g., CO2, CO, NO, NO2, O3, H2S and VOC), which connect directly to the main board inside the enclosure. These sensors provide continuous, real-time data for monitoring specific gas concentrations.