The Bender IR425-D4-1 is a high-performance ISOMETER® designed for insulation monitoring in unearthed AC, AC/DC, and DC power systems (IT systems). It is particularly effective in modern power systems containing converters, rectifiers, and variable-frequency drives that can introduce high earth leakage capacitances. Utilizing the patented AMP Plus measurement principle, this device provides reliable and precise monitoring to ensure electrical safety and prevent unplanned downtime. The IR425-D4-1 features two separately adjustable response values, an LC display for easy reading of measured values and device status, and an internal history memory for fault analysis. Its ability to automatically adapt to the system’s leakage capacitance makes it a versatile and essential component for a wide range of industrial applications.