Allows the user to detect multiple gases with one sensor base by merely swapping sensor heads. Designed designed for use with all portable monitors. The Aeroqual Sensors are housed within an interchangeable ‘sensor head’ that attaches to the Aeroqual S500 Portable Air Quality Monitor base. You can choose from up to 30 different sensor heads. Each sensor contains a single gas or particle sensor. Swapping sensor heads takes seconds and no configuration or re-calibration is required.