The Fluke 1577 insulation multimeters combine a digital insulation tester with a full-featured, True RMS digital multimeter in a single compact, handheld unit, which provides maximum versatility for both troubleshooting and preventative maintenance. The 1577 has a large display with backlight. It measures AC/DC voltage, DC millivolts, AC/DC milliamps, resistance (Ω) and continuity. For added user protection the meters have live circuit detection which prevents an insulation test if voltage greater than 30V is detected. They also have auto-discharge of capacitive voltage as an added user protection. The auto power off feature saves battery life.