Finds wood and metal studs and joists behind walls, floors, and ceilings up to 1-1/2″ deep. For safety, it indicates the presence of AC voltage while scanning. Locates standard 120/240V AC wiring. Finds wires in plastic conduit or Romex cable. Select between 3/4″ and 1-1/2″ scan depth. SpotLite pointing with audio signal, and LEDs indicate stud edges. Instant calibration. Operates on 9-volt battery (included).