Amphenol SGX Sensortech's VQ500 series is a catalytic combustible gas sensor used to sense hydrocarbon gasses like methane. Within the VQ500 series there are specific sensors that are able to detect most combustible gases and vapors and ammonia at LEL levels. The thermal conductivity version will detect most gases at % volume concentrations which have thermal conductivities different from that of air. Amphenol SGX Sensortech offers a complete range of miniature, fully certified, flameproof sensor heads containing a high quality, low power pellistor pair optimized for the detection of combustible gases or % volume gases in thermal conductivity mode. They have an outline identical to modern miniature electrochemical cells and are ideally suited for use in portable instruments.