Stud Finder, Center-finding Stud Finder Sensor Wall Scanner- 4 in 1 Multi Function Wall Finder Detector with Digital LCD Display & Sound Warning for Studs/Wood/Metal/Live AC Wires Detection Widely Application: Multi-scanner stud finder for Wood, Metal, Deep, AC Current. Quickly locates edges and center of wood ,wall studs, metal pipes,wooden joist, rebar behind walls, floors and ceilings, also indicates the presence of live AC wire. Easy to Use: Only 2 buttons, first press ON/OFF power button, then select the Mode Switch Button,after that just press the Scan button(at the left side of the device) and scan horizontally across the object surface. Calibration: Before detection, please keep the scan button pressed for 1-2 sec, and it will get calibrated. Beep sound will remind you when job done. You may need to recalibrate your device if the button was released accidentally at the beginning or you think it need to do so during the process. Center Finding - AC wire warning flags will show on the LCD whenever live wires was monitoring in three detecting modes. Show Column will elevating as wood stud finder approach item's center, and the highest Easy to Read: Features with LCD backlight, providing a clear look even in low light conditions, which indicates detection mode, center pointing, low battery indication. Audio indication, with beep sound for reminding.