Product Package Contents: 1 * Detector, 1 * Instructions ( without battery) 1.Precise Wall Scanner: The stud detector adopts an advanced sensor system to ensure its accuracy after tests and upgrades. It can quickly locate stud wood metal and live AC power lines. Whether you are a professional, a homeowner or a DIY enthusiast, you can use this handy tool to gain great benefits. Simply calibrate this tool before each scan to drill holes. 2.4-in-1 Scanner plus Depth Sensing: The wall scanner includes four different scanning modes for wood, joist, joist, metal, AC wire and deep embedded objects behind floors, ceilings and walls. STUD mode can detect wooden joists and joists in plasterboard up to 3.8 cm. METAL mode can detect pipe, steel rod, aluminum and copper up to 6 cm in length. AC power is suitable for live and live wires with a depth of 2 inches. 3.LED Display Clear Sound Warning: The wall nail sensor has a large LED screen display and a loud and clear sound warning. As you move this tool along the wall, the LED screen display will show you a clear direction and accurate object position, and its audible warning will indicate the edge or center of the object on the wall. This makes your DIY projects easier and faster. 4.Auto Calibration for Efficient Scanning: The stud detector will be calibrated automatically when power on. Make sure you calibrate in a place where there are no nearby studs or AC power cords. In STUD mode you only need to calibrate on the wall. In METAL and AC mode, please calibrate in air. Then you will get accurate alerts to avoid drilling holes in metal or AC wires or other accidents. 5.Multi-Function: This wall detector can quickly find the metal and wooden AC wires hidden behind the house walls. Help locate the exact bolts when installing TVs, cabinets, garage shelves, etc.