Zircon StudSensor SL Edge Finder ZIRZ62138 We took the acclaimed StudSensor and upgraded it with our innovative SpotLite Pointing System.The StudSensor SL stud finder is the 21st century incarnation of the original stud finder that Zircon introduced to the world in 1980. Powered by proprietary technology, it finds the edges of wood and metal studs and features Zircon"s patented SpotLite Pointing System. It"s the sure way to securely hang pictures, shelves, mirrors, and more.- Locates the edge of wood or metal studs behind drywall up to 19 mm thick. - A red LED lights up every time a stud edge is approached. - The patented SpotLite Pointing System and green LED signals when the stud edge is reached. - 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 density and a green LED TruCal light alerts the user when the tool is calibrated and ready to scan. ZIRZ62138