Technology has advanced to the point that a metal-detection unit can report subtle differences in two similar metallic targets. With sophisticated detectors, operators can determine whether a particular concealed target is lead, iron, aluminum, gold, copper, or silver, based on the metal's conductivity. Detectors also can be programmed to search for a single, predetermined target, regardless of size, while disregarding all other metals. A detector's electromagnetic field penetrates air, water, earth, wood, stone, concrete, bone, skin, and tissue. Learning to operate a metal detector is similar to learning the intricacies of a camera. Although mastering the use of a metal detector is not difficult, considerable skill must be developed to obtain optimum results. For metal detector operators to maintain and improve their proficiency, they must use the equipment in a self-paced program. Officers trained in metal detection should be encouraged to use it regularly in an off- duty, hobby capacity. Metal detectors detect only metal and cannot be expected to locate other items of evidence. They also cannot detect one metal through another metal. This article discusses how to select a metal detector, based on simplicity of design and operation, automatic ground canceling, ruggedness, and other features. A case study of the usefulness of a metal detector is provided.