This center detect Stud Finder has a detection depth of 1-1/2 In. for wood and metal. Traditional stud sensors locate the edge of the stud, but this product locates the center for a more efficient read, even when held at an angle. Plus, it is constantly calibrating to save time during use. Once the stud is located, an audible alert and directional LED (light emitting diode) lights clearly notify the user. The center of the stud can easily be marked with the center marking channel. AC and live wire detection for added safety. Features a slim profile for easy use and storage. AAA batteries included.