This insulation tester is capable of measuring 250V, 500V or 1,000V test voltages and insulation resistance up to 2000M ohms. When undertaking power installations, the 420001-insulation tester can provide special help to test wiring. This unit can provide 125V, 250V, 500V and 1000V source for the test, and under each range it can supply 1mA current to feed the capacitance load. With the auto-range function, it can measure up to 4,000 Megaohm with the resolution of 1Kohm. The unit features a large, easy to read dual display with analog bar graph and backlight, and min/max recording & data hold functions. Auto-discharge of capacitive voltage for added user protection, live circuit detection prevents insulation test if voltage >30V for added safety.This is a complete kit which includes 6 AA batteries, users manual, test leads, "crocodile clips", strap and a hard plastic carrying case. Meets IEC10101, CATIII 1000V Large dual display with analog bar graph and backlight Displays insulation resistance and test voltage simultaneously Auto-discharge of capacitive voltage for added user protection Live circuit detection prevents insulation test if voltage >30V Min/Max recording & Data Hold Function 1mA test current for Megohm range at rated voltage 200mA short current for continuity range Additional test voltages 125V,250V,500V,1000V Test hold & lock function for easy operation Easy to carry testing package Over Range Indication Low Battery Indication