The GA-72Cd Locator detects the magnetic field of iron and steel objects. It provides audio detection signals that peak in frequency when the locator’s tip is held directly over the target. The GA-72Cd has the option of nulling or peaking. Only two Controls! Designed for one-hand operations, the On/Off-Sensitivity and Volume controls are located on the underside of the cover. This provides easy access, protects the knobs, and contributes to their overall ruggedness and dependability.