Buyee Vc60b+ Insulation Resistance Tester Meter Megohmmeter [Energy Class A++] Double Alarm: Sound and Light Alarm. Display returns to zero when a short-cut resistance occured, to Special design to Mount battery easily. An accurate, reliable and easy-to-use insulation tester Large LCD display, LCD backlight ON/OFF key, easy to read. Strong anti- magnetic and anti-jamming fu Full function protection, anti high voltage circuit design. Unit symbol display, easy to use. High v Double Power source: 1.5V AA battery x6pcs, or external DC 9V power sourc(both not included)