The Bosch GMS120 Wall Scanner has three modes -- wood, metal or live AC wiring -- and can detect both ferrous and non-ferrous metals, wood studs and live AC wires. It will detect live wires when in any mode, and provide a live wire warning. In metal and live wire modes, the GMS120 is always calibrated; in wood mode, it automatically calibrates when the tool is placed on the wall. The illuminated LCD display shows the location of an object's depth, width and edge and displays the automatic center finder for locating the center of a detected wood or metal object. The GMS120, with its multi-sensor detection technology, has a suggested price of $79.