The AEMC Non-Contact AC Voltage Detector NC-1 is a pen-style detector with a pocket clip, voltage sensitivity of 100 to 240VAC, and frequency of 50/60Hz, for checking electrical voltage in outlets and elsewhere. A flashing light and audible warning indicate the presence of AC voltage. The detector takes two 1.5V AAA alkaline batteries (included). It is for indoor use and in accordance with over voltage 600V Category III, Pollution Degree 2.