Zircon MultiScanner 740 Electronic Wall Scanner with Built-In Erasable Wall Marker/Center Finding and Edge Finding Stud Finder/Metal Detector/Live AC Wire Detection - FFP Zircon's MS 740 is a multi-surface scanner with 4 modes that allows you to detect and mark the location of studs, metal and live AC wiring ACT (Auto Correcting Technology) that automatically corrects common user errors, such as when scanning begins over a stud, in addition to the unique floating head design that keeps the sensor flat on rough and textured surfaces to increase the accuracy of results Both StudScan and DeepScan modes locate the edges, center and direction of wood or metal studs and joists; Metal Scan mode finds both non-ferrous metal (such as copper pipe) and ferrous metal (such as rebar) even through lath and plaster; AC Scan finds and traces live, unshielded electrical AC wires WireWarning Detection indicates the presence of live, unshielded electrical AC wiring while scanning in StudScan, DeepScan, and Metal Scan modes Integrated erasable wall marker enables users to mark targets with the simple push of a button