The top three buttons are 1. drywall, 2. concrete or brick walls, and 3. live wires only. If you should use the device, you must remove the rings and the clock, because the device can detect the metallic objects. A static charge is built up around the device. To get rid of it you have to hold the other hand to the wall. It is important that you guide the device slowly. Too fast movements it will not work.