The stanley intelli tools stud sensor 150 uses electronic signals to locate edges of studs joists or live ac wires through drywall or other common building materials once the edge of the stud has been detected the stud sensor 150 displays red leds and sounds an audible tone a v shaped marking channel with an led allows accurate marking depth detection can be selected by an activation button for 12mm 12 inch 25mm 1 inch and 38mm 112 inch the ergonomic design and soft grips ensure a comfortable us