1- Xtreme Locator used to find an Xspot or Xspot-mini, accurate to 1 inch and able to confirm that you have found an Xspot device not a nail, screw or some piece of metal. By using the reverse polarity of magnets one side of the Xtreme tool will be attracted and the other side will push away when it is up against another magnet. 1-The Xcentric tool is used once you have confirmed you are on the right location. The Xcentric will center on the Xspot or Xspot-mini behind the wall accurate to .25 inches. Once located then make a mark in each of the four holes, take the Xcentric off the wall, connect the four marks with two lines creating the signature X , drill in the center of the X (like the crosshairs of a rifle scope) mark whatever size opening you need for that location, drill the appropriate sized hole.