Multifunction Wall Detector Scanner Large Area Sensor For Metal Nonmetal AC Wire Finding With LCD Display And Beep Multifunction Wall Detector Scanner Large Area Sensor For Metal Nonmetal AC Wire Finding With LCD Display And Beep Test operation: After the sampling is successful, do not release the power switch and move along the surface to be tested. When the instrument detects a foreign object, the red indicator light starts to light up in sequence. When the LED is all on and makes a "dripping" sound, use a pencil to do the next step. Check and release the power switch. Put the instrument in the opposite direction of the surface to be sampled and approach the marking position. When the instrument detects a foreign object, the Red indicator lights begin to illuminate in sequence. When the LEDs are all on and make a "dripping" sound, use a pencil to mark the next mark and release the power switch. Repeat the test several times, if the alarm is issued, that is, there may be support pillars (foreign objects) under the middle area. When there are no metal objects or other foreign objects under it, it will not flash or sound. To get the accuracy of the test results, you can test it several times. Parameters: Power supply: 6F22 Type 9V battery (this product does not have a battery) Product size: 145x62x25mm Product weight: about 71g (without battery) This instrument is designed on the principle that the change in the density of the substance below the surface of the detected object causes the frequency of the detector to change. The maximum detection depth is 19mm below the surface of the uniform object, the error of the detection range is 3mm, and the range of the detected object cannot be less than 1200mm2 Package list: 1*naked watch (without battery) 1*Manual 1*Packing carton _x000D_ _x000D_