Zircon StudSensor Pro LCD quickly and easily locates the edges of wood and metal studs and joists behind walls floors and ceilings. Its easy-to-read display screen indicates stud edge the patented SpotLite Pointing System shines a beam of light on the wall to identify the target and WireWarning detection indicates the presence of live AC voltage. Stud Scan mode locates the edges of wood or metal studs up to 3/4" (19 mm) deep; DeepScan mode doubles the scanning depth to 1-1/2" (38 mm); Easy-to-read LCD display indicates when a stud edge is approached; Patented SpotLite Pointing System and audio tone signals when the stud edge is reached; WireWarning detection indicates the presence of live unshielded electrical wiring up to 2" (51 mm) deep; Should scanning begin over a stud Zircon's patented "over-the-stud" indicator alerts the user to start the scan in a new location; Patented TruCal technology calibrates to any wall's density and the TruCal icon indicates when the tool is ready and calibrated. Clamshell package