Light and sound. When there is no metal object or voltage circuit nearby, it not flash and sound. When the test is over, please cut off the power. When the detector's metal detection head (METAL) is moved parallel to the of the object to be measured, if the voltage loop is detected, the detector voltage The detection part (VOLTAGE) moves parallel to the of the object to be measured. When the detector is close to a metal object or a voltage circuit, it flash Keep away from the object to be measured, turn on the knob switch and adjust it slowly, so that it is just in the state of no sound and no light, and detect metal The detector cannot test the AC voltage in metal pipes, metal walls or deep parts., Weight: 0.27998707274 Pounds, Manufacturer: Jaywool