The Model S4000TH Intelligent Sensor is a microprocessor-based transmitter designed for use with General Monitors thin film metal oxide semiconductor (TFMOS) sensors. This unit features one person calibration and can virtually self-calibrate by simply activating a magnetic switch and applying gas. It is designed to detect hydrogen sulfide in parts per million (ppm) levels and provide status indication and alarm outputs. CSA, FM, ATEX, CE Marking approved. SIL 2/3 suitable.