The UL-certified POLI Multi-Gas Detector offers four- or five-gas monitoring of toxic gases, oxygen, combustibles, carbon dioxide and volatile organic compounds. The POLI MP400 is a basic detector that uses diffusion sampling for confined space entry compliance, with oxygen, LEL, carbon monoxide and hydrogen sulfide sensors. The POLI MP400P (shown) is an advanced model with a built-in pump that allows a full selection of sensors, including electrochemical, pellistor, non-dispersive infrared and photoionization detector.