Dual Detector ModesThe default AC voltage automatic measuring range is 48-1000V, besides, you can also press MODE button to switch to manual mode (with wide measuring range between 12-1000V. meeting all your needs.< /p> Adjustable Sensitivity Switch to manual mode. You can adjust the sensitivity by turning the sensitivity adjustment knob. Low sensitivity mode allows more accurate determination of field conditions in complex lines. High sensitivity mode detects the condition of walls and hidden lines. Sensor Chip Indicator When detecting voltage, indicator lights will produce three different color: Green -- Low, Yellow -- MID, Red -- High. Live Wire TestThis non-contact voltage tester can distinguish online and zero line easily. Signal indicator according to different, loud insistent beeps within caused red light signal is online. LED Flashlight and Visual Sound IndicatorIndicators emit yellow and red lights, buzzer alarms at different frequencies (low, medium, high). Visual and audible alarm to ensure your safety. LED flashlight design makes you more convenient to work in dark environment.