MagNail magnetized nails s are used for land surveying and construction layout when critical points are needed to be set in asphalt, wood, or other such surfaces that a nail could be set into. Since most of the points we set end up in the real world, we have to be able to visually find them in the future. In addition the points set by one particular surveyor may need to be recovered by yet another. Before mag nails was PK nails which are still available today. The creation of mag nails came from the need to find these set points by use of a locator or more commonly known by you and me as a metal detector. Since mag nails are magnetic, and larger in size than a PK they are found quicker and with greater ease using a locator. Furthermore Mag nails have a zinc coating to prevent corrosion and rusting longer than PK nails. This coating makes the nail shiny and more visible longer when set into different surfaces. However the most important improvement was the thickness of the striking head surface and the overall strength and durability of the nails; these nails are better able to withstand striking blows without the head coming off or the nail itself bending. So the slogan really means something, as the Mag's can be struck harder with a hammer, and found farther using a metal detector.