The Schonstedt GA-52Cx Locator detects deviation created the magnetic field of the earth around iron/ steel objects and energized power lines. The strength of the deviation identifies the location of those objects. An audible noise that peaks in frequency when the locator's tip is held directly over the target locates the target. The locator is not capable of finding copper, aluminum, gold, etc. Small iron objects can be located in shallow depths, larger iron/steel objects can be located at deeper depths. The larger the mass of the iron/steel, the deeper it can be detected.