The Zircon® StudSensor™ center finding electronic wall scanner comes loaded with the latest technology in density detecting software and circuitry. Using patented CenterVision® technology, the SS 70 easily locates the center and edges of wood and metal studs and joists behind walls, floors, and in ceilings with just one pass. The specialized SpotLite® Pointing System and an audio tone indicate the location of the target. In StudScan mode, the SS 70 locates the center and edges of shallower wood or metal studs up to 3/4 of an inch (19 millimeters) deep. Switch over to DeepScan® mode by quickly pressing the power button twice to double the scanning depth to 1.5 inches (38 millimeters). The StudSensor™ 70 is programmed with a WireWarning® detection feature that indicates the presence of live unshielded electrical wires up to 2 inches (50 millimeters) deep when using both stud scan modes. The SS 70 also comes equipped with a built-in, erasable marker enabling you to mark the hazards or studs with the simple push of a button. To get started, install one brand new 9-volt alkaline battery (not included). Place the unit flat against the wall and calibrate it. Once you hear the calibration beep and see the "Ready" LED light, continue to hold the power button and slowly slide the tool across the surface. As the stud detector approaches the edge of a stud, the red LEDs progressively light from the bottom up in both scanning modes. The top lighted "Center" LED, SpotLite® Pointing System, and audio tone all indicate when the stud's center is found. Make sure to note whether the WireWarning® detection is alerting to live, unshielded AC wiring before drilling between the two marks into the center of the stud. With the Zircon® StudSensor™ 70, you can safely maneuver through the most complicated of projects with the professional confidence that comes from owning a Zircon®.