The HIOKI IR4059 is a 5-range digital insulation tester developed for EV maintenance and industrial electrical work, covering standard test voltages from 50 V to 1000 V. The high-voltage lock mechanism eliminates electric shock risks caused by misoperation, while the 0.3s ultra-fast comparator instantly judges insulation pass/fail. The supplied multi-function remote test lead avoids repeated trips to the main unit, with built-in lighting suitable for dim garages and equipment rooms. It supports 200 mA high-current continuity test and automatic AC/DC voltage detection. Optional Bluetooth module enables wireless data synchronization to mobile Excel spreadsheets. Rugged drop-resistant construction and auto discharge protection make it a professional, safe measuring tool for EV service and factory electrical insulation inspection.