The POLI multi-gas meters offer 4- or 5-gas monitoring of toxic gases, oxygen (O2), combustibles (LEL), carbon dioxide (CO2) and volatile organic compounds (VOCs). The POLI MP400P is an advanced model with built-in pump that allows a full selection of sensors for a wide range of applications, including Confined Space Entry, while the POLI MP400 is a basic, 4-gas diffusion detector for worker safety at hazardous locations. Smart sensors carry calibration and ID information with them for quick exchange in the field during Hazmat response. Specific sensors include electrochemical (EC) for carbon monoxide (CO), hydrogen sulfide (H2S), ammonia (NH3), hydrogen cya- nide (HCN), hydrogen chloride (HCl), hydrogen fluoride (HF), chlorine (Cl2), chlorine dioxide (ClO2), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ethylene oxide, methyl mercaptan, and others. Also available are pellistor for LEL level combustibles, non-dispersive infrared (NDIR) for Vol% level CO2 or hydrocarbons, and photo-ionization detector (PID) for ppm level VOCs. Use of combination CO/H2S or SO2/H2S sensors allow up to 5 gas measurements in a single instrument. The MP400P has rugged construction and easy-to-learn 2-button oper- ation. The unique Man-Down alarm feature notifies nearby workers if the user becomes incapacitated.