Zircon StudSensor 40 Edge Finding Stud Sensor with Live AC WireWarning Detection and Patented SpotLite Pointing System The Zircon SS 40 electronic stud scanner detects the edges of wood and metal studs and alerts you of live AC wires helping you easily find studs and avoid hazards while mounting a TV, hanging cabinets, installing garage shelving and more StudScan mode locates the edges of wood or metal studs up to 0.75 inches (19 mm) deep while DeepScan mode locates targets up to 1.5 inches (38 mm) deep WireWarning Detection indicates the presence of live, unshielded electrical AC wiring while scanning in StudScan and DeepScan modes Patented "Over the Stud" Indicator and SpotLite Pointing System ensure the SS 40 provides trustworthy results One fully charged 9V battery, not included, is required for the stud scanner to run at optimal performance