Safety First: It emits multiple alarms by sound and light. When the voltage is detected, the tip emits red light and beep. If the higher the measured voltage is, or the closer it is to the voltage source, it will beep her with onehigher frequency. At the same time, the screen will turn red or green, red means high voltage and live wires are detected, green means low voltage and neutral wires are detected. Non-contact: with NCV inductive probe for AC voltage simply place the tip near a terminal block, outlet, or power cord. When the tip glows red and the pen beeps, you know voltage is present. Of thelive line detector can detect the live or neutral wire automatically. Ideal for breakpoint testing. Handy voltage tester for electricians, homeowners. Dual range: Detects standard and low voltage (12-1000VAC) for more sensitive and flexible measurements. Press the S button to adjust sensitivity and low range for doorbells, thermostats, irrigation wiringadjust etc. The NCV sensor automatically detects the voltage and displays it on the bar graph. Safety Level: IEC CAT III 1000V CAT IV 600V, meets CE requirements. The electrical tester is safe double insulated. High voltage warning to warn you about voltage over 90V, the screen will turn red and the safety icon on the screenlights up. Compact Design: Bright LED flashlight for working in low state, low power indication when battery voltage is below 2.5V. Auto power off after 3 minutes of no operation or signal detection. Pocket size, pen hookallows you to carry them in your shirt pocket