Specifications: Model: HW-710Authentication: CE FCC RHOSPackaging size: 174 x 76 x 41MMWeight: 170GBattery: 9V battery 6F22 (not included)Purpose: Quickly locate wood, metal, and AC wires hidden in the walls, floors, and ceilings of a house. It can work in Flat noodles, wallpaper, wood floor, acoustic ceiling, spray painted wall and other places. Prevent you from encountering danger when installing televisions, cabinets, garage racks, etc. Detection Mode: Stud Mode: In stud mode, there are 3 scan modes o choose for properly thick of the scanning surface:x1 or 2"Scan Mode can detect 1 or 2 in. (13mn) deep.x1"Scan Mode can detect 1 in. (25mm)deep.x1 1 or 2"Scan Mode can detect 1 1 or 2 in.(38mm) deep.If you don't know the depth of the detection, it is recommended to use 1 or 2"scan mode first. When 1 or 2"scan mode is not detected, use 1"or 1 1 or 2"scan mode instead. Metal Mode: The detection of magnetic metal can be as deep as 3.2 in. (80mm)(diameter 15mm galvanized steel tube)It can detect non-magnetic metals up tc 2.4 in. (60mm) (diameter 13mm copper tube). AC Mode: Detect unshielded AC live wire up to 2 in. (51mm) deep.