1、[Automatic Detection] Intelligent identification of the live wire and the neutral wire, automatic detection, sound and light alarm, making the operation more convenient. 2、[High Accuracy] With LED light, no fear of darkness, NCV sensor head, make the measurement more accurate. 3、[High Sensitivity] Just adjust the sensitivity (low, medium, high) by adjusting the sensitivity button to measure the voltage. 4、[Automatically Shut Down] Voltage tester will automatically shut down when there is no operation for 3 minutes and no voltage signal is detected. 5、[LCD Screen] Electric tester pen with LCD screen, AC high voltage sign, low power reminder, distinguish empty line or real time line, and use 2 x AAA batteries (battery not included).