Stud Magnet™ is ideal for the home improvement and picture hanging markets. The powerful 4 in magnet features super strong neodymium magnets and is permanently magnetized. Stores neatly with a Magnetic Shield™ that prevents it from attracting other tools or nails in a tool box. Stud Magnet™ is easy-to-use and does not depend on batteries or mechanical parts. Simply remove the Magnetic Shield™ and move magnet across the wall's surface until it attracts to the hidden drywall screw or nail where the stud is located. The magnet holds itself in place to mark the location. Use the notched end of the Stud Magnet™ to set the nail. Attach a string with a small washer to the opposite end of the Stud Magnet™ to create a plumb line for placing additional nails or screws in a straight line.