About this item: 1. SAFETY FIRST : It will send out multiple alarms through sound and light. When the voltage is detected, the tip will send out red light and beep. When the higher the sensed voltage is, or the closer it is to the voltage source, it beeps at a higher frequency. At the same time, the light will be red or yellow, red means high voltage and live wire are detected, yellow means low voltage and null wire are detected. 2. Accurately Multi-ranging Measurement: The electrical tester accurately detects AC Voltage ranging from 12V to 1000V, and distinguish them into 2 Voltage levels (low, high). NCV sensitivity automatically adjusts from low and high while indicating Voltage level with audible beep. 3. High Efficiency: Press and hold the switch for two seconds to start the machine, As Long As Voltage is Detected, the Led in the Tester Pen will Shine 4. COMPACT DESIGN: Bright LED flashlight for work in dim ares; Low-Power-Indicator when battery voltage is below 2.5V; Automatic Power Off after 3 minutes without operation or signal detection; Pocket-sized, pen hook allows you to carry it in your shirt pocket. 5. SECURITY LEVEL: IEC rated CAT III 1000V CAT IV 600V, Meets CE requirements; The electrical tester is safely double insulated. High Voltage Alert to warn you of voltage above 90V, the screen turn red and the safety symbol on the screen shines.