OneStep tool finds the center and edges of wood and metal studs and joists up to 1-1/2 deep in walls, floors, and ceilings. Perfect for both professional builders and home improvement enthusiasts. WireWarning Alert indicates the presence of unshielded hot electrical wiring. An easy-to-read LCD screen indicates direction, center, and edges of studs. A signal strength indicator helps determine the targets depth. CenterVision technology locates the center of wood and metal studs with just one pass. SpotLite Pointing System and audio alert identify stud centers instantly. ACT Auto Correcting Technology checks calibration 10 times per second and recalibrates automatically to ensure accuracy. Uses 1 9-volt battery (included).