The DirectSense TVOC comes with a 10.6-eV PID sensor for ppb- or ppmrange measurement of total volatile organic compounds (TVOCs). Relative humidity and temperature sensors are included. Users can add up to three electrochemical sensors for the following gases: O3, NH3, NO2, NO, SO2, H2S, HCN, EtO, O2, Cl2, HCl, H2, AsH3, CO, and others. Probes for CO2, particle counts, differential pressure and other parameters may also be simultaneously monitored. Desktop PC software is included.