RGY are industrial grade gas leak detectors for up to 4 zones using accurate linear catalytic 4..20mA transmitters. The unit has 4 adjustable alarm thresholds, and can be used for natural gas, LPG gas and for carbon monoxide. 230Vac power supply. DIN-rail mounted with clear LCD display. Each of the 4 zones have pre-alarm relay output and alarm relay output. Additional auxiliary relay available for sensor failures. Sensor failure is also displayed on the central unit.