The ICM Controls ICM492D Line Voltage Monitor is a single-phase protection device designed to continuously monitor incoming voltage from 80–300 VAC. It measures and displays RMS voltage, detecting overvoltage and undervoltage conditions before they can damage connected equipment. When voltage falls outside adjustable limits, its SPDT relay changes state and the unit signals a fault, w... https://www.partshnc.com/icm-controls-icm492d-line-voltage-monitor-80-300v-1ph