To make the best out of it, it is very important to use this app properly. We provide help within the app. More information is provided in our website www.goldsequence.com. You can also see this instruction video
We have tested this app in multiple buildings with different phones. It works pretty well for drywall if used properly. Even if you cover the drywall with a extra layer of 1/4 inch thick ceramic tile, the app can still work. That being said, the app is not without its limits. This app won''t work well if the variation of magnetic field strength becomes too weak to pick up. For example, if you live in a old house with plaster wall and the plaster layer is more than 1/4 inch thick, the app will probably not work well. Even if your house uses drywall, if the size of the drywall screws is too small, it could generate problems for this app. So we agree that this app is not for every house. However, we do believe that it can do good things for many people in many houses.