Unlike an electronic stud finder, this one never needs batteries; plus, it indicates the thickness of your wallboard, so you can choose the correct screw or anchor. Of particular usefulness is the Stud Finder's unparalleled utility at locating ceiling joists, especially on textured ceilings which often prevent electronic or even magnetic stud finders from being effective.
Simply press the nose straight into the wallboard so the fine needle (only 0.027" diameter) can penetrate. If the nose does not retract all the way into the body of the finder, you've found your stud (you'll feel when the needle hits it). If you can push the needle all the way through, however, simply move it over and try again. That's all there is to it.
The markings on the side of the nose show you how thick the wallboard is. They are shown in millimeters, but it's easy to check the distance against any ruler. Click here to Download a PDF* formatted informational / instructional sheet.(*Note: Requires Adobe Acrobat Reader)