Sonin 50215 4-in-1 Stud, Moisture, Metal and Voltage Detector Measures moisture levels present in wood, drywall, carpets and more from 8-22% Helps you easily locate and detect wood or memtal sunds, beams and joist behind walls Non-contact voltage detection helps you trade and locate live AC wire behind walls Detects and locates hidden metals, stell and copper pipes, metals frams included bot ferrous and nonferrous) behind walls Microprocessor based instrument with automatic calibration to ensure accuracy.