3-in-1 Design: Suitable for wood, metal and AC current. Quickly locates wood, wall studs, metal pipes, wooden joist, rebar and live AC wire behind walls, floors and ceilings. Easy Reading: With LCD digital display and continuous sound warning to indicate you the location of the edges of the studs. Scanning Depth: Detects stud up to 0.71 inches (18mm) depth, metal up to 1.2 inches (30mm), and presence of live wire up to 3 inches (50mm). Battery Operated: This wall scanner is operated by 3pcs AAA batteries (NOT INCLUDED). Low battery indication and auto shut off to save battery life. Simple Operation: After battery installation, the unit is turned on with a long beep. After auto power off, press TEST button for two seconds to turn on again. See more product details 3-in-1 Design: Suitable for wood, metal and AC current. Quickly locates wood, wall studs, metal pipes, wooden joist, rebar and live AC wire behind walls, floors and ceilings. Easy Reading: With LCD digital display and continuous sound warning to indicate you the location of the edges of the studs. Scanning Depth: Detects stud up to 0.71 inches (18mm) depth, metal up to 1.2 inches (30mm), and presence of live wire up to 3 inches (50mm). Battery Operated: This wall scanner is operated by 3pcs AAA batteries (NOT INCLUDED). Low battery indication and auto shut off to save battery life. Simple Operation: After battery installation, the unit is turned on with a long beep. After auto power off, press TEST button for two seconds to turn on again.